€¦ · Web view(b) The racing car has a mass of 1250 kg. When the brake pedal is pushed down a...
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04 Terminal Velocity 291 minutes 291 marks Q1. The diagram shows a shuttlecock that is used for playing badminton. The shuttlecock weighs very little. When you drop it from a height of a few metres, it accelerates at first but soon reaches a steady speed. Explain, as fully as you can: (a) why the shuttlecock accelerates at first, .................................................................. .............................................................. .... .................................................................. .............................................................. .... .................................................................. .............................................................. .... (2) (b) why the shuttlecock reaches a steady speed.
Transcript of €¦ · Web view(b) The racing car has a mass of 1250 kg. When the brake pedal is pushed down a...
04 Terminal Velocity
291 minutes
291 marks
Q1. The diagram shows a shuttlecock that is used for playing badminton.
The shuttlecock weighs very little.When you drop it from a height of a few metres, it accelerates at first but soon reaches a steady speed.
Explain, as fully as you can:
(a) why the shuttlecock accelerates at first,
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(b) why the shuttlecock reaches a steady speed.
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(Total 5 marks)
Q2. A small object falls out of a balloon.
Choose words from the list to complete the sentences below.
friction gravity air pressure
accelerates falls at a steady speed slows down
• The weight of an object is the force of ............................................ which acts on it.
• When you drop something, first of all it ............................................... .
• The faster it falls, the bigger the force of ........................................... which acts on it.
• Eventually the object ............................................. .(Total 4 marks)
Q3. A man’s car will not start, so two friends help him by pushing it.
By pushing as hard as they can for 12 seconds they make the car reach a speed of3 metres per second.
(a) Calculate the acceleration they give to the car.
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.............................................................................................. Answer ................ m/s2
(2)
(b) Whilst pushing the car the two friends together do a total of 2400 joules of work. Calculate their total power.
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............................................................................................ Answer ................ watts(2)
(c) Another motorist has the same problem. The two friends push his car along the same stretch of road with the same force as before.
It takes them 18 seconds to get the second car up to a speed of 3 metres per second.
What does this tell you about the mass of the second car?(You can ignore forces of friction.)
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(d) On a flat stretch of a motorway a lorry driver changes into top gear. He then makes the lorry go as fast as he can.
The graph shows what happens to the speed of the lorry.
Explain why the speed of the lorry increases at first but then levels out.
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(Total 9 marks)
Q4. A sky-diver steps out of an aeroplane.
After 10 seconds she is falling at a steady speed of 50m/s.
She then opens her parachute.
After another 5 seconds she is once again falling at a steady speed.
This speed is now only 10m/s.
(a) Calculate the sky-diver’s average acceleration during the time from when she opens her parachute until she reaches her slower steady speed. (Show your working.)
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(b) Explain, as fully as you can:
(i) why the sky-diver eventually reaches a steady speed (with or without her parachute).
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(ii) why the sky-diver’s steady speed is lower when her parachute is open.
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(c) The sky-diver and her equipment have a total mass of 75kg. Calculate the gravitational force acting on this mass. (Show your working.)
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Answer ........................................ N(1)
(Total 8 marks)
Q5. Choose words from this list to complete the sentences below.
balanced electricity gravity
joules magnetism newtons
When you drop something it falls.
This is because it is pulled to the Earth by ............................................................................
We measure forces in units called .........................................................................................
When a falling object reaches the ground, it stops moving.
This means that the forces acting on it are now ....................................................................(Total 3 marks)
Q6. When a gun is fired, a very large force acts on the bullet for a very short time.
The change in momentum of the bullet is given by the following relationship:
force (N) × time(s) = change in momentum (kg m/s)
(a) An average force of 4000 newton acts for 0.01 seconds on a bullet of mass 50g.
Calculate the speed of the bullet. (Show your working.)
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Answer ............................................... m/s(4)
(b) The bullet is fired horizontally. In the short time it takes for the bullet to reach its target, its horizontal speed has fallen to 80% of its initial speed.
(i) Explain why the speed of the bullet decreases so quickly.
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(ii) Calculate the percentage of its original kinetic energy the bullet still has when it reaches its target.
(Show your working.)
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(Total 10 marks)
Q7. A book weighs 6 newtons.
A librarian picks up the book from one shelf and puts it on a shelf 2 metres higher.
(a) Calculate the work done on the book. [Show your working].
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(b) The next person to take the book from the shelf accidentally drops it.
The book accelerates at 9.8m/s².
Use this information to calculate the mass of the book. [Show your working].
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Answer ................................. kg.(3)
(c) If the book was dropped from an aeroplane high in the sky, it would accelerate to begin with. Eventually it would fall at a steady speed.
Explain, in as much detail as you can, why this happens.
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(Total 9 marks)
Q8. A bouncy ball is dropped vertically from a height of 2.00 m onto the floor. The graph shows the height of the ball above the floor at different times during its fall until it hits the floor after 0.64 s.
(a) What is the average speed of the ball over the first 0.64 s? Show clearly how you work out your answer.
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Average speed = ....................................... m/s(1)
(b) After it hits the floor the ball bounces back to a height of 1.25 m. It reaches this height 1. 16 s after it was dropped. Plot this point on the grid above and sketch a graph to show the height of the ball above the floor between 0. 64 s and 1.16 s.
(3)
(c) (i) The ball bounces on the floor 0.64 s after being dropped. How long after being dropped will it be before it bounces a second time?
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(ii) What distance will the ball travel between its first and second bounce?
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(d) The ball was held stationary before being dropped. On the graph and your sketch marktwo other points X1 and X2, where the ball is stationary, and in each case explain why the ball is not moving.
X1 ...............................................................................................................................
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X2 ..............................................................................................................................
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(Total 8 marks)
Q9. In bungee jumping, a fixed rubber cord is fastened to the jumper’s ankles.
The graph shows how the bungee jumper’s velocity changes during part of the jump.
(a) Calculate the acceleration of the bungee jumper between 2 and 4 seconds. Show your working.
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Acceleration = ................................ m/s2
(3)
(b) Describe, in as much detail as you can, what happens to the bungee jumper after 4 seconds.
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(Total 6 marks)
Q10. When you transfer energy to a shopping trolley, the amount of work done depends on theforce used and the distance moved.
Complete the table by using the correct units from the box.
joule (J) metre (m) newton (N)
The first one has been done for you.
Quantity Unit
energy (transferred) joule
force
distance (moved)
work done
(Total 2 marks)
Q11. When a bungee-jump is made the jumper steps off a high platform. An elastic cord from the platform is tied to the jumper.The diagram below shows different stages in a bungee-jump.Forces A, B and C are forces acting on the jumper at each stage.
moving down moving down moving downlarge acceleration small acceleration slowing acceleration
diagram X diagram Y diagram Z
(a) Name force A.
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(b) The motion of the jumper is shown in the diagrams.By comparing forces A, B and C, state how the motion is caused in:
(i) diagram X;
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(ii) diagram Y;
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(iii) diagram Z.
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(3)
(c) The table gives results for a bungee cord when it is being stretched.
STRETCHING FORCE (N) 100 200 400 600 800
LENGTH OF CORD (m) 20 24 32 40 48
(i) Plot a graph of these results on the graph paper.
(3)
(ii) Use the graph to find the length of the cord before it was stretched.
Length .................... m(1)
(Total 8 marks)
Q12. A hot air balloon called Global Challenger was used to try to break the record for travelling round the world.The graph shows how the height of the balloon changed during the flight.
The balloon took off from Marrakesh one hour after the burners were lit and climbed rapidly.
(a) Use the graph to find:
(i) the maximum height reached.
Maximum height .............................. metres.
(ii) the total time of the flight.
Total time ........................................... hours.(2)
(b) Several important moments during the flight are labelled on the graph with the letters A,B, C, D, E and F.At which of these moments did the following happen?
(i) The balloon began a slow controlled descent to 2500 metres. ........................
(ii) The crew threw out all the cargo on board in order to stopa very rapid descent. .......................
(iii) The balloon started to descend from 9000 metres. .......................(3)
(Total 5 marks)
Q13. A sky-diver jumps from a plane.
The sky-diver is shown in the diagram below.
(a) Arrows X and Y show two forces acting on the sky-diver as he falls.
(i) Name the forces X and Y.
X ..........................................................
Y ..........................................................(2)
(ii) Explain why force X acts in an upward direction.
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(iii) At first forces X and Y are unbalanced.
Which of the forces will be bigger? .......................................(1)
(iv) How does this unbalanced force affect the sky-diver?
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(b) After some time the sky-diver pulls the rip cord and the parachute opens.
The sky-diver and parachute are shown in the diagram below.
After a while forces X and Y are balanced.
Underline the correct answer in each line below.
Force X has
increased / stayed the same / decreased.
Force Y has
increased / stayed the same / decreased.
The speed of the sky-diver will
increase / stay the same / decrease.(3)
(c) The graph below shows how the height of the sky-diver changes with time.
(i) Which part of the graph, AB, BC or CD shows the sky-diver falling at a constant speed?
................................................(1)
(ii) What distance does the sky-diver fall at a constant speed?
Distance .............................. m(1)
(iii) How long does he fall at this speed?
Time .................................... s(1)
(iv) Calculate this speed.
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Speed .............................. m/s(2)
(Total 14 marks)
Q14. A racing driver is driving his car along a straight and level road as shown in the diagram below.
(a) The driver pushes the accelerator pedal as far down as possible. The car does not accelerate above a certain maximum speed. Explain the reasons for this in terms of the forces acting on the car.
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(b) The racing car has a mass of 1250 kg. When the brake pedal is pushed down a constant braking force of 10 000 N is exerted on the car.
(i) Calculate the acceleration of the car.
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(ii) Calculate the kinetic energy of the car when it is travelling at a speed of 48 m/s.
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(iii) When the brakes are applied with a constant force of 10 000 N the car travels a distance of 144 m before it stops. Calculate the work done in stopping the car.
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(Total 16 marks)
Q15. A driver is driving along a road at 30 m/s. The driver suddenly sees a large truck parked across the road and reacts to the situation by applying the brakes so that a constant braking force stops the car. The reaction time of the driver is 0.67 seconds, it then takes another 5 seconds for the brakes to bring the car to rest.
(a) Using the data above, draw a speed-time graph to show the speed of the car from the instant the truck was seen by the driver until the car stopped.
(5)
(b) Calculate the acceleration of the car whilst the brakes are applied.
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Answer = .................................... m/s2
(3)
(c) The mass of the car is 1500 kg. Calculate the braking force applied to the car.
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Answer = .................................... N(3)
(d) The diagrams below show what would happen to a driver in a car crash.
(i) Explain why the driver tends to be thrown towards the windscreen.
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(ii) During the collision the front end of the car becomes crumpled and buckled. Use this information to explain why such a collision is described as “inelastic”.
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(iii) The car was travelling at 30 m/s immediately before the crash. Calculate the energy which has to be dissipated as the front of the car crumples.
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(Total 19 marks)
Q16. (a) When a car is driven efficiently the engine gives a constant forward pull on the car as the car accelerates to its maximum speed. During this time frictional forces and air resistance oppose the forward motion of the car. The sketch graphs below show how the car’s speed increases when only the driver is in the car, and when the driver has a
passenger in the car.
(i) How does the acceleration of the car change with time?
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(ii) What conclusion can be made about the resultant (net) forward force on the car as its speed increases?
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(ii) On the graph, draw a line to show how you would expect the car’s speed to vary if it carried three passengers.
(1)
(b) The manufacturer of a family car gave the following information.
Mass of car 950g
The car will accelerate from 0 to 33 m/s in 11 seconds.
(i) Calculate the acceleration of the car during the 11 seconds.
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Answer .....................................................(2)
(ii) Calculate the force needed to produce this acceleration.
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Answer .................................. N (2)
(iii) The manufacturer of the car claims a top speed of 110 miles per hour. Explain why there must be a top speed for any car.
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(Total 9 marks)
Q17. The manufacturer of a family car gave the following information.
Mass of car 950 kg
The car will accelerate from 0 to 33 m/s in 11 seconds.
(a) Calculate the acceleration of the car during the 11 seconds.
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(b) Calculate the force needed to produce this acceleration.
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(2)
(c) The manufacturer of the car claims a top speed of 110 miles per hour. Explain why there must be a top speed for any car.
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(Total 7 marks)
Q18. (a) A shopping trolley is being pushed at a constant speed. The arrows represent the horizontal forces on the trolley.
(i) How big is force P compared to force F?
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(ii) Which one of the distance-time graphs, K, L or M, shows the motion of the trolley? Draw a circle around your answer.
(1)
(b) Complete the sentence by crossing out the two words in the box that are wrong.
Acceleration is the rate of change of (1)
(c) Three trolleys, A, B and C, are pushed using the same size force. The force causes each trolley to accelerate.
Which trolley will have the smallest acceleration?
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Give a reason for your answer.
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(Total 5 marks)
##
The table shows the braking distances for a car at different speeds and kinetic energy. The braking distance is how far the car travels once the brakes have been applied.
Braking distance in m
Speed of car in m/s
Kinetic energy of car in kJ
5 10 40
12 15 90
20 20 160
33 25 250
45 30 360
(a) A student suggests, “the braking distance is directly proportional to the kinetic energy.”
(i) Draw a line graph to test this suggestion.
(3)
(ii) Does the graph show that the student’s suggestion was correct or incorrect? Give a reason for your answer.
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(iii) Use your graph and the following equation to predict a braking distance for a speed of 35 metres per second (m/s). The mass of the car is 800 kilograms (kg). Show clearly how you obtain your answer.
kinetic energy = ½ mv2
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Braking distance = ........................................ m(2)
(iv) State one factor, apart from speed, which would increase the car’s braking distance.
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(b) The diagram shows a car before and during a crash test. The car hits the wall at14 metres per second (m/s) and takes 0.25 seconds (s) to stop.
(i) Write down the equation which links acceleration, change in velocity and time taken.
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(ii) Calculate the deceleration of the car.
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Deceleration = ........................................ m/s2
(1)
(iii) In an accident the crumple zone at the front of a car collapses progressively. This increases the time it takes the car to stop. In a front end collision the injury to the car passengers should be reduced. Explain why. The answer has been started for you.
By increasing the time it takes for the car to stop, the ...................................
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(Total 11 marks)
Q20. The apparatus shown is used to compare the motion of a coin with the motion of a piece of paper as they both fall.
(a) When the tube is filled with air the coin falls faster than the piece of paper. Why?
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(b) The air in the tube is removed by the vacuum pump. The tube is turned upside down.State two ways in which the motion of the coin and piece of paper will change compared to when there was air in the tube.
1 .................................................................................................................................
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(Total 3 marks)
Q21. The diagram shows an orbiter, the reusable part of a space shuttle. The data refers to a typical flight.
(a) (i) What name is given to the force which keeps the orbiter in orbit around the Earth?
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(ii) Use the following equation to calculate the kinetic energy, in joules, of the orbiter while it is in orbit.
kinetic energy = ½ mv2
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Kinetic energy = ............................. joules(2)
(iii) What happens to most of this kinetic energy as the orbiter re-enters the Earth’s atmosphere?
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(b) After touchdown the orbiter decelerates uniformly coming to a halt in 50 s.
(i) Give the equation that links acceleration, time and velocity.
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(ii) Calculate the deceleration of the orbiter. Show clearly how you work out your answer and give the unit.
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Deceleration = ...............................(2)
(c) (i) Give the equation that links acceleration, force and mass.
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(ii) Calculate, in newtons, the force needed to bring the orbiter to a halt. Show clearly how you work out your answer.
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Force = ............................ newtons(1)
(Total 9 marks)
Q22. (a) Two skydivers jump from a plane. Each holds a different position in the air.
A B
Adapted from Progress with Physics by Nick England, reproduced by permission of Hodder Arnold
Complete the following sentence.
Skydiver ........................ will fall faster because.......................................................
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The diagram shows the direction of the forces acting on one of the skydivers.
Adapted from Progress with Physics by Nick England, reproduced by permission of Hodder Arnold
(b) In the following sentences, cross out in each box the two lines that are wrong.
(i) Force X is caused by (1)
(ii) Force Y is caused by (1)
(iii) When force X is bigger than force Y, the speed of the
skydiver will (1)
(iv) After the parachute opens, force X (1)
(c) How does the area of an opened parachute affect the size of force Y?
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(Total 7 marks)
Q23. (a) The diagram shows the horizontal forces that act on a moving motorbike.
(i) Describe the movement of the motorbike when force A equals force B.
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(ii) What happens to the speed of the motorbike if force B becomes smaller than force A?
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(b) The graph shows how the velocity of a motorbike changes when it is travelling along a straight road.
(i) What was the change in velocity of the motorbike in the first 5 seconds?
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(ii) Write down the equation which links acceleration, change in velocity and time taken.
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(iii) Calculate the acceleration of the motorbike during the first 5 seconds.Show clearly how you work out your answer and give the unit.
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Acceleration = .............................................(3)
(c) A car is travelling on an icy road.
Describe and explain what might happen to the car when the brakes are applied.
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(d) Name three factors, other than weather conditions, which would increase the overall stopping distance of a vehicle.
1 ..................................................................................................................................
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(Total 13 marks)
Q24. The diagram shows a sky-diver in free fall. Two forces, X and Y, act on the sky-diver.
(a) Complete these sentences by crossing out the two lines in each box that are wrong.
(i) Force X is caused by .(1)
(ii) Force Y is caused by .(1)
(b) The size of force X changes as the sky-diver falls. Describe the motion of the sky-diver when:
(i) force X is smaller than force Y,
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(ii) force X is equal to force Y.
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(Total 5 marks)
Q25. The diagram shows the forces on a small, radio-controlled, flying toy.
(a) (i) The mass of the toy is 0.06 kg.Gravitational field strength = 10 N/kg
Use the equation in the box to calculate the weight of the toy.
weight = mass × gravitational field strength
Show clearly how you work out your answer and give the unit.
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Weight = .................................................(3)
(ii) Complete the following sentence by drawing a ring around the correct line in the box.
When the toy is hovering stationary in mid-air, the lift force is
bigger than
the same as
smaller than
the weight of the toy.
(1)
(b) When the motor inside the toy is switched off, the toy starts to accelerate downwards.
(i) What does the word accelerate mean?
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(ii) What is the direction of the resultant force on the falling toy?
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(iii) Does the momentum of the toy increase, decrease or stay the same?
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Give a reason for your answer.
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(Total 8 marks)
Q26. (a) A car driver makes an emergency stop.
The chart shows the ‘thinking distance’ and the ‘braking distance’ needed to stop the car.
Calculate the total stopping distance of the car.
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Stopping distance = ................................................. m(1)
(b) The graph shows how the braking distance of a car driven on a dry road changes with the car’s speed.
The braking distance of the car on an icy road is longer than the braking distance of the car on a dry road.
(i) Draw a new line on the graph to show how the braking distance of the car on an icy road changes with speed.
(2)
(ii) Which two of the following would also increase the braking distance of the car?
Put a tick ( ) next to each of your answers.
rain on the road
the driver having drunk alcohol
car brakes in bad condition
the driver having taken drugs (2)
(c) The thinking distance depends on the driver’s reaction time.
The table shows the reaction times of three people driving under different conditions.
Car driver Condition Reaction timein seconds
A Wide awake with no distractions 0.7
B Using a hands-free mobile phone 0.9
C Very tired and listening to music 1.2
The graph lines show how the thinking distance for the three drivers, A, B and C, depends on how fast they are driving the car.
(i) Match each graph line to the correct driver by writing A, B or C in the box next to the correct line.
(2)
(ii) The information in the table cannot be used to tell if driver C’s reaction time is increased by being tired or by listening to music.
Explain why.
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(Total 9 marks)
(i) How many hours does it take for the count rate to fall from 300 counts per minute to 150 counts per minute?
Time = .................................................. hours(1)
(ii) What is the half-life of technetium-99?
Half-life = ............................................. hours(1)
(Total 7 marks)
Q27. (a) The diagram shows an aircraft and the horizontal forces acting on it as it moves along a runway. The resultant force on the aircraft is zero.
(i) What is meant by the term resultant force?
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(ii) Describe the movement of the aircraft when the resultant force is zero.
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(b) The aircraft has a take-off mass of 320 000 kg. Each of the 4 engines can produce a
maximum force of 240 kN.
Use the equation in the box to calculate the maximum acceleration of the aircraft.
resultant force = mass × acceleration
Show clearly how you work out your answer and give the unit.
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Acceleration = ...............................................(3)
(c) As the aircraft moves along the runway to take off, its acceleration decreases even though the force from the engines is constant.
Explain why.
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(Total 7 marks)
Q28. (a) The diagram shows a steel ball-bearing falling through a tube of oil.The forces, L and M, act on the ball-bearing.
What causes force L?
.....................................................................................................................................(1)
(b) The distance – time graph represents the motion of the ball-bearing as it falls through the oil.
(i) Explain, in terms of the forces, L and M, why the ball-bearing accelerates at first but then falls at constant speed.
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...........................................................................................................................(3)
(ii) What name is given to the constant speed reached by the falling ball-bearing?
...........................................................................................................................(1)
(iii) Calculate the constant speed reached by the ball-bearing.
Show clearly how you use the graph to work out your answer.
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Speed = ............................................................ m/s(2)
(Total 7 marks)
Q29. The diagram shows the horizontal forces acting on a car of mass 1200 kg.
(a) Calculate the acceleration of the car at the instant shown in the diagram.
Write down the equation you use, and then show clearly how you work out your answer and give the unit.
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Acceleration = .............................(4)
(b) Explain why the car reaches a top speed even though the thrust force remains constant at 3500 N.
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........................................................................................................................(3)
(c) The diagram shows a car and a van.
The two vehicles have the same mass and identical engines.
Explain why the top speed of the car is higher than the top speed of the van.
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........................................................................................................................(4)
(Total 11 marks)
Q30. The diagram shows the forces acting on a skydiver.
Draw a ring around the correct answer to complete the following sentences.
air resistance.
friction.
gravity.
(a) Force J is caused by
(1)
air resistance.
gravity.
weight.
(b) Force K is caused by
(1)
bigger than
the same as
smaller than
(c) When the skydiver jumps from the aircraft, force J is
accelerates downwards.
accelerates upwards.
falls at a steady speed.
force K and the skydiver
(2)(Total 4 marks)
Q31. A cyclist travelling along a straight level road accelerates at 1.2 m/s2 for 5 seconds.The mass of the cyclist and the bicycle is 80 kg.
(a) Use the equation in the box to calculate the resultant force needed to produce this acceleration.
resultant force = mass × acceleration
Show clearly how you work out your answer and give the unit.
........................................................................................................................
........................................................................................................................
Resultant force = ...........................................(3)
(b) The graph shows how the velocity of the cyclist changes with time.
(i) Complete the following sentence.
The velocity includes both the speed and the ........................of the cyclist.(1)
(ii) Why has the data for the cyclist been shown as a line graph instead of a bar chart?
...............................................................................................................
...............................................................................................................(1)
(iii) The diagrams show the horizontal forces acting on the cyclist at three different speeds. The length of an arrow represents the size of the force.
A B C
Which one of the diagrams, A, B or C, represents the forces acting when the cyclist is travelling at a constant 9 m/s?
...............................................................................................................
Explain the reason for your choice.
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...............................................................................................................(3)
(Total 8 marks)
Q32. The miners working in a salt mine use smooth wooden slides to move quickly from one level to another.
(a) A miner of mass 90 kg travels down the slide.
Calculate the change in gravitational potential energy of the miner when he moves 15 m vertically downwards.
gravitational field strength = 10 N/kg
Use the correct equation from the Physics Equations Sheet.
Show clearly how you work out your answer.
........................................................................................................................
........................................................................................................................
Change in gravitational potential energy = .................................................. J(2)
(b) Calculate the maximum possible speed that the miner could reach at the bottom of the slide.
Use the correct equation from the Physics Equations Sheet.
Show clearly how you work out your answer.
Give your answer to an appropriate number of significant figures.
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........................................................................................................................
Maximum possible speed = .................................................. m/s(3)
(c) The speed of the miner at the bottom of the slide is much less than the calculated maximum possible speed.
Explain why.
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........................................................................................................................(3)
(Total 8 marks)
Q33. (a) The diagram shows the forces acting on a parachutist in free fall.
The parachutist has a mass of 75 kg.
Calculate the weight of the parachutist.
gravitational field strength = 10 N/kg
Use the correct equation from the Physics Equations Sheet.
Show clearly how you work out your answer and give the unit.
........................................................................................................................
........................................................................................................................
Weight = ....................................................(3)
(b) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
The graph shows how the vertical velocity of a parachutist changes from the moment the parachutist jumps from the aircraft until landing on the ground.
Using the idea of forces, explain why the parachutist reaches a terminal velocity and why opening the parachute reduces the terminal velocity.
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........................................................................................................................(6)
(c) A student wrote the following hypothesis.
‘The larger the area of a parachute, the slower a parachutist falls.’
To test this hypothesis the student made three model parachutes, A, B and C, from one large plastic bag. The student dropped each parachute from the same height and timed how long each parachute took to fall to the ground.
(i) The height that the student dropped the parachute from was a control variable.
Name one other control variable in this experiment.
...............................................................................................................(1)
(ii) Use the student’s hypothesis to predict which parachute, A, B or C, will hit the ground first.
Write your answer in the box.
Give a reason for your answer.
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...............................................................................................................(2)
(Total 12 marks)
Q34.A car has an oil leak. Every 5 seconds an oil drop falls from the bottom of the car onto the road.
(a) What force causes the oil drop to fall towards the road?
........................................................................................................................(1)
(b) The diagram shows the spacing of the oil drops left on the road during part of a journey
Describe the motion of the car as it moves from A to B.
........................................................................................................................
Explain the reason for your answer.
........................................................................................................................
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........................................................................................................................
........................................................................................................................(3)
(c) When the brakes are applied, a braking force slows down and stops the car.
(i) The size of the braking force affects the braking distance of the car.
State one other factor that affects the braking distance of the car.
...............................................................................................................(1)
(ii) A braking force of 3 kN is used to slow down and stop the car in a distance of 25 m.
Calculate the work done by the brakes to stop the car and give the unit.
Use the correct equation from the Physics Equations Sheet.
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Work done =..................................................(3)
(Total 8 marks)
Q35.A car has an oil leak. Every 5 seconds an oil drop falls from the bottom of the car onto the road.
(a) What force causes the oil drop to fall towards the road?
........................................................................................................................(1)
(b) The diagram shows the spacing of the oil drops left on the road during part of a journey
Describe the motion of the car as it moves from A to B.
........................................................................................................................
Explain the reason for your answer.
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........................................................................................................................(3)
(c) When the brakes are applied, a braking force slows down and stops the car.
(i) The size of the braking force affects the braking distance of the car.
State one other factor that affects the braking distance of the car.
...............................................................................................................(1)
(ii) A braking force of 3 kN is used to slow down and stop the car in a distance of 25 m.
Calculate the work done by the brakes to stop the car and give the unit.
Use the correct equation from the Physics Equations Sheet.
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Work done =..................................................(3)
(Total 8 marks)
M1. (a) reference to
• weight / force of gravity / acting downwards
• unbalanced (by any upwards force)for 1 mark each
2
(b) ideas that forces balance(d)gains 1 mark
butweight / force of gravity / downwards force balanced by friction / air resistance / drag / upwards force
gains 2 marks
latter increases with speed
(accept arrows or relevant length and direction if clearly labelled,as answers to parts (a) and (b))
for 1 further mark3
[5]
M2. • gravity
• accelerates
• friction
• falls at a steady speedeach for 1 mark
[4]
M3. (a) evidence of or
gains 1 mark
but 0.25 or ¼gains 2 marks
2
(b) evidence of or
gains 1 mark
but 200gains 2 marks
2
(c) idea that
second car has a bigger mass
(allow bigger weight/heavier)gains 1 mark
butsecond car has 1.5 times bigger massorsecond car has mass of 1200 kg
gains 2 marks2
(d) friction/resistance increases with speedgains 1 marks
butfriction with/resistance of air increases with speedgains 2 marks
• increase in speed because driving force greater than friction
• steady speed when friction = driving force
orincreases in speed until friction = driving forceeach for 1 further mark to maximum of 3
3[9]
##
(a) evidence of or
gains 1 mark
(credit 50/10 or 5 with 1 mark) NOT 40/10 or 50/5
but 8 [N.B. negative not required]gains 2 marks
units metres per second per second or (metres per second squared or m/s²)for 1 mark
3
(b) (i) idea thataccelerates at first due to gravityair/wind resistancefriction/resistance/drag with air increases with speedeventually gravity and friction cancel balanceor (no net/accelerating force) [NOT terminal velocity]
each for 1 mark3
(ii) ideaa bigger resistance/friction/drag at any given speed (credit a bigger drag (factor))
for 1 mark1
(c) evidence of × 10 / × 9.8 / × 9.81 or 750/735(75)for 1 mark
1[8]
M5. gravitynewtonsbalanced
each for 1 mark[3]
M6. (a) any evidence of: momentum = mass × velocity (words, symbols or numbers) appropriate re-arrangement mass as 0.05kg
each gains 1 mark
but 800gains 4 marks
4
(b) (i) any reference to friction with air/air resistancegains 1 mark
but idea that friction with air/air resistance is high (at high speed)gains 2 marks
2
(ii) any evidence of: k.e. v2 or k.e. = ½ mv2
final k.e.initial k.e.either initial or final k.e. correctly calculated (i.e. 16000; 10240)
each gains 1 mark
but (0.8)2
gains 3 marks
but 64%(credit 0.64)gains 4 marks (also credit e.c.f)
4[10]
M7. (a) WD = force × distance or 6 × 2gains 1 mark
but 12 gains 2 marksunits J/joules [credit Nn]for 1 mark
3
(b) 0.6 (i.e. using the recalled 10N/kg)gains 1 mark
but evidence of force = mass × accelerationor of correct substitution e.g. 6/9.8
gains 2 marks
but 0.61 (2...)gains 3 marks
3
(c) any reference toinitial acceleration due to gravity(force due to) friction/air resistance
each for 1 mark
ideas thatthis increases as speed increasesforces eventually balance
each for 1 further mark9
[9]
M8. (a) 3.125accept 3.1 or 3.12
1
(b) plotted at 1. 15 – 1.17, 1.24 – 1.28across on the second from 1.2, up between first and second line
1
sketch curve steeper near 0.64 s fairly smooth curve bending1
to become pretty well horizontal at 1.16, 1.251
(c) (i) 1.68 or 1.7working is 2(l.16 – 0.64) + 0.64 =
(ii) 2.5 m unit requiredconsequential marking applies here
1
(d) X1 at 0.64 s, 0 m
it is in contact with the floor or theball changes direction or thedownward force is balanced by thereaction of the floor
accept the ball is hitting the floordo not credit it has hit the floor
1
X2 at 1.16 s, 1.25m it is at the top of its bounceaccept the ball changes direction or has run out of KE
2[8]
M9. (a) 7.5correct answer with no working = 3 if incorrect allow 1 mark for (change in velocity from graph =) 15
1 mark for
2 marks for
N.B. correct answer from the incorrectly recalled relationship
= 2 marks3
(b) (4 – 5 seconds) the bungee jumper slows down (decelerates)1
(the rubber cord) stops the fall
1
(5 – 6 seconds) the bungee jumper starts moving (accelerating) upwards(in the opposite direction)
max 2 marks if no correct indication of time1
[6]
M10. newton or N
metre or m
joules or Jall three correct 2 markstwo or one correct 1 mark
[2]
M11. (a) weight or gravity or gravitationalfor 1 mark
1
(b) (i) only force A acts / force A > air resistance / gravity / weightfor 1 mark
1
(ii) force A > force Bfor 1 mark
1
(iii) force C > force Afor 1 mark(Forces A, B and C need not be used, description of forces are OK)
1
(c) (i) graph points all correct ± little squaregains 2 marks
one point wronggains 1 mark
2+ points wronggains 0 mark
appropriate line – good freehand OK
gains 1 markBar chart gets 0, but if points clear can get 23
(ii) 16 or candidates own intercept should be 16 m in range 1-19if no kinks on graph line
for 1 mark1
[8]
M12. (a) (i) 9400(m)for 1 mark
1
(ii) 26.5(hours)for 1 mark
1
(b) (i) Ffor 1 mark
1
(ii) Dfor 1 mark
1
(iii) Bfor 1 mark
1[5]
M13. (a) (i) air resistance/drag/friction (or upthrust) weight/gravitational pull/gravity
for 1 mark each1
(ii) air resistance/friction acts in opposite direction to motion1
(iii) Y1
(iv) the sky-diver accelerates/his speed increasesin downward direction/towards the Earth/falls
for 1 mark each
2
(b) force X has increased force Y has stayed the same the speed of the sky-diverwill stay the same
for 1 mark each3
(c) (i) CD1
3
(iv) 10 (but apply e.c.f. from (ii) and (iii))gets 2 marks
or 500/50 or d/tgets 1 mark
2[14]
M14. (a) there is a (maximum) forward forcedrag/friction/resistance (opposes motion) (not pressure)increases with speedtill forward and backward forces equalso no net force/acceleration
any 4 for 1 mark each4
(b) (i) F = ma10 000 = 1250aa = 8m/s2
for 1 mark each4
(ii) ke = 1/2 mv2ke = 1/2 1250.482ke = 1 440 000Jfor 1 mark each
4
(iii) W = FdW = 10 000.144W = 1 440 000J
for 1 mark each4
[16]
M15. (a) Each scale optimumElse both half sizeStraight line joining 30,0 to 30,0.67 to 0, 5.67
any 5 for 1 mark each5
(b) 6Else a = 30/5
gets 2 marks
Else a = v/tgets 1 mark
3
(c) 9000Else F = 6 × 1500
gets 2 marks
Else F = magets 1 mark
3
(d) (i) Driver has forward momentumWhich is conservedGiving drive relative forward speed to car
for one mark each3
(ii) If inelastic ke lostHere ke does work crumpling car
for 1 mark each2
(iii) Car stops in 75mgets 1 mark
W = F.d or 9000 × 75gets 1 mark
W = 675 000 JOR ke = 1/2 mv2
gets 1 mark
ke = 1/2.1500.302ke = 675 000 J3
[19]
M16. (a) (i) decreasesfor 1 mark
1
(ii) decreasesfor 1 mark
1
(iii) lower speed everywherefor 1 mark
1
(b) (i) 3 a = or a =
gains 1 mark
1
ms–2
gains 1 mark1
(ii) 2850 ecfgains 2 marks
else workinggains 1 mark
2
(iii) air resistance/frictional forces increase with speed;till frictional force = max forward engine force;when acceleration is zero
(incorrect statement – 1 mark)
or (limitation on maximum speed for safety-1 mark)any two for 1 mark each
2[9]
M17. (a) 3gains 1 mark
m/s2
gains 1 mark
else working gains 1 mark2
(b) 2850 ecfgains 1 mark
Ngains 1 mark
else workinggains 1 mark
2
(c) friction/air resistance increases with speed;till frictional = max forward force;then force/acceleration is zero
for 1 mark each
alternative limitation for safetygains 1 mark only
3[7]
M18. (a) (i) same size1
(ii) K1
(b) velocity1
(c) C1
greatest mass or because it’s heavieraccept biggest loadaccept heaviest or more weightdo not accept fullerdo not accept more itemsdo not accept it’s loadeddo not accept loaded mostignore references to time as neutral
1[5]
M19. (a) (i) linear scales useddo not credit if less than half paper used
1
points plotted correctlyall of paper used
1
(straight) line of best fit drawnallow a tolerance of half square
1
(ii) correct and straight line through originall needede.c.f. if their (a)(i) is straight but not through the origin - incorrect because line does not go through origincredit a calculation that shows proportionality
1
(iii) 62 ± 0.5 (m)credit 1 mark for KE = 490000 or 490kJcredit 1 mark for correct use of graph clearly shown
2
(iv) any one from: wet or icy or worn or smooth roadaccept slippery slope
brakes wornaccept faulty brakes
car heavily loadedworn tyresdownhill slopedo not accept anything to do with thinking distance e.g. driver tired or drunk
1
(b) (i) acceleration =
accept correct transformation
accept
accept m/s2 =
do not accept acceleration =1
(ii) 56accept –56
1
(iii) deceleration is reducedaccept deceleration is sloweraccept acceleration
1
force on car and or passengers is reducedaccept an answer in terms of change in momentum for full credit
1[11]
M20. (a) air(resistance) has greatest effect on paper1
(b) paper or both fall faster1
(both) fall togetheraccept same speed or rate
1[3]
M21. (a) (i) gravity/weight1
(ii) 2193750000000 or 2.19 × 1012
not 2.1912
allow 1 mark for the correct conversion to 7500 (m/s)allow one mark for answer 2193750(J)
2
transferred to heatignore extras of sound and light
accept changed to heataccept lost due to friction
1
(b) (i) acceleration =
accept word speed instead of velocity
accept a =
or correct rearrangementdo not accept
even if subsequent calculation correct
can gain credit if subsequent calculation correct1
(ii) 2ignore + or – signs
m/s2 1accept m/s/s or ms2
2
(c) (i) force = mass × accelerationaccept correct rearrangementaccept F = m × ado not accept
unless subsequent calculation correct1
(ii) 156 000accept 78 000 × their (b)(ii)(only if (b)(i) correct)
1
[9]
M22. (a) B
more aerodynamic or most streamlined shape orsmaller (surface) area
accept less air/wind resistance or less drag or less friction clothing traps less air or rolled up into ball or arms, legs drawn inaccept converse
2
(b) (i) gravity1
(ii) air resistance1
(iii) go up1
(iv) stays the same1
(c) bigger the area, the bigger force Yaccept the converse
or bigger the area more dragaccept when the parachute opens then force Y bigger
or bigger the area more air resistanceneed the relation of area to force
1[7]
M23. (a) (i) constant speeddo not accept normal speeddo not accept it is stopped / stationary
1
in a straight lineaccept any appropriate reference to a directionconstant velocity gains 2 marks‘not accelerating’ gains 2 marksterminal velocity alone gets 1 mark
1
(ii) goes down owtteaccept motorbike (it) slows down
1
(b) (i) 20 (m/s)ignore incorrect units
1
(ii) acceleration =
do not accept velocity for change in velocityaccept change in speed
accept or
or a =
do not accept 1
(iii) 4
or their (b)(i) ÷ 5allow 1 mark for correct substitution
2
m/s2
m/s/s or ms or metres persecond squared or metres persecond per second
1
(c) vehicle may skid / slideloss of control / brakes lock / wheels lockaccept greater stopping distance or difficult to stop
1
due to reduced friction (between tyre(s) and road)accept due to less gripdo not accept no friction
1
(d) any three from:do not accept night time / poor vision
• increased speed
• reduced braking force
• slower (driver) reactionsNB specific answers may each gain credit eg tiredness (1), drinking alcohol (1), using drugs (1), driver distracted (1) etc
• poor vehicle maintenancespecific examples may each gain credit eg worn brakes or worn tyres etc
• increased mass / weight of vehicleaccept large mass / weight of vehicle
• poor road surface
• more streamlinedif candidates give three answers that affect stopping distance but not specific to increase award 1 mark only
3[13]
M24. (a) (i) frictionaccept any way of indicating the correct answer
1
(ii) gravityaccept any way of indicating the correct answer
1
(b) (i) accelerates or speed / velocity increasesaccept faster and faster (1 mark)do not accept faster pace / falls fasteror suggestions of a greater but constant speed
1
downwards / fallsaccept towards the Earth / groundthis may score in part (b)(ii) if it does not score here and there is no contradiction between the two parts
1
(ii) constant speed / velocity or terminal velocity / speed or zero accelerationstays in the same place negates credit
1[5]
M25. (a) (i) 0.6allow 1 mark for correct substitution
2
newtonsaccept Ndo not accept naccept Newtons
1
(ii) the same as1
(b) (i) changed velocityaccept increased/ decreased for changeaccept speed for velocityaccept change directionaccept getting faster/ sloweraccept start/ stop movingaccept correct equation in terms of change in speed or change in velocity
1
(ii) down(wards)accept towards the groundaccept ↓do not accept south
1
(iii) increase
velocity is increasingcan only credit second mark if answer is increase
or it is acceleratingaccept speed for velocityaccept is moving faster
1
accept an answer in terms of resultant force downwardsmention of weight/ mass increasing negates second mark
1[8]
M26. (a) 53 (m)1
(b) (i) Similar shape curve drawn above existing line going through (0, 0)allow 1 mark for any upward smooth curve or straight upward line above existing line going through (0, 0)
2
(ii) rain on road1
car brakes in bad condition1
(c) (i) all three lines correctly labelledallow 1 mark for one correctly labelled
top line – Caccept 1.2
middle line – Baccept 0.9
bottom line – Aaccept 0.7
2
(ii) any two from:
• (table has) both variables are togetheraccept tired and music as named variables
• both (variables) could/ would affect the reaction time
• cannot tell original contributionaccept cannot tell which variable is affecting the drive (the most)
• need to measure one (variable) on its ownaccept need to test each separately
• need to control one of the variables2
[9]
M27. (a) (i) a single force that has the same effect as all the forces combinedaccept all the forces added / the sum of the forces / overall force
1
(ii) constant speed (in a straight line)do not accept stationary
or constant velocity1
(b) 3allow 1 mark for correct substitution into transformed equationaccept answer 0.003 gains 1 markanswer = 0.75 gains 1 mark
2
m/s2
1
(c) as speed increases air resistance increasesaccept drag / friction for air resistance
1
reducing the resultant force1
[7]
M28. (a) gravityaccept weightdo not accept massaccept gravitational pull
1
(b) (i) Initially force L greater than force Maccept there is a resultant force downwards
1
(as speed increases) force M increasesaccept the resultant force decreases
1
when M = L, (speed is constant)accept resultant force is 0accept gravity/weighty for Laccept drag/ upthrust/resistance/friction for Mdo not accept air resistance for M but penalise only once
1
(ii) terminal velocity1
(iii) 0.15accept an answer between 0.14 – 0.16an answer of 0.1 gains no credit
allow 1 mark for showing correct use of the graph2
[7]
M29. (a) 1.25allow 1 mark for correct resultant force ie 1500Nallow 2 marks for correct transformation and substitution
ie allow 1 mark for a correct transformation but clearly substituting an incorrect value for force
eg = 3
m/s 2
1
(b) as speed increases so does the size of the drag forceaccept frictional force / resistive force / air resistance for drag
1
eventually the drag force becomes equal to the thrust1
the resultant force is now equal to zero and thereforethere is no further acceleration1
(c) the car and van will reach top speed when the forwardforce equals the drag force
accept air resistance / frictional / resistive force for drag force1
the drag force at any speed is smaller for the car thanfor the van
1
as the car is more streamlined1
therefore the car’s drag force will equal the forward forceat a higher speed
1
allow converse throughout[11]
M30. (a) gravity1
(b) air resistance1
(c) bigger than1
accelerates downwards1
correct order only[4]
M31. (a) 96allow 1 mark for correct substitutionie 80 × 1.2
2
newton or Nallow Newtondo not allow n
1
(b) (i) direction1
(ii) velocity and time are continuous (variables)answers must refer to both variablesaccept the variables are continuous / not categoricaccept the data / ‘it’ is continuousaccept the data / ‘it’ is not categoric
1
(iii) C1
velocity is not changingthe 2 marks for reason may be scored even if A or B are chosenaccept speed for velocityaccept speed is constant (9 m/s)accept not deceleratingaccept not acceleratingaccept reached terminal velocity
1
forces must be balanced
accept forces are equalaccept arrows are the same length / size
orresultant force is zero
do not accept the arrows are equal1
[8]
M32. (a) 13 500 (J)allow 1 mark for correct substitution, ie 90 x 10 x 15 provided no subsequent step shown
2
(b) 17or
correctly calculated and answer given to 2 or 3 significant figuresaccept 17.3allow 2 marks for an answer with 4 or more significant figures, ie 17.32orallow 2 marks for correct substitution, ie 13 500/ their (a) = ½ x 90 x v2
orallow 1 mark for a statement or figures showing KE = GPE
3
(c) work is done1
(against) friction (between the miner and slide)accept ‘air resistance’ or ‘drag’ for friction
1
(due to the) slide not (being perfectly) smoothaccept miners clothing is rough
or
causing (kinetic) energy to be transferred as heat/internal energy of surroundingsaccept lost/transformed for transferredaccept air for internal energy of surroundings
1[8]
M33. (a) 750allow 1 mark for correct substitution, ie 75 × 10 provided no subsequent step shown
2
newton(s) / Ndo not accept n
1
(b) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also refer to the Marking Guidance, and apply a ‘best-fit’ approach to the marking.
0 marksNo relevant content.
Level 1 (1-2 marks)There is a brief attempt to explain why the velocity / speed of the parachutist changes.or the effect of opening the parachute on velocity/speed is given.
Level 2 (3-4 marks)The change in velocity / speed is clearly explained in terms of force(s)ora reasoned argument for the open parachute producing a lower speed.
Level 3 (5-6 marks)There is a clear and detailed explanation as to why the parachutist reaches terminal velocity anda reasoned argument for the open parachute producing a lower speed
examples of the physics points made in the response to explain first terminal velocity
• on leaving the plane the only force acting is weight (downwards)accept gravity for weight throughout
• as parachutist falls air resistance acts (upwards)accept drag / friction for air resistance
• weight greater than air resistance orresultant force downwards
• (resultant force downwards) so parachutist accelerates
• as velocity / speed increases so does air resistance
• terminal velocity reached when air resistance = weightaccept terminal velocity reached when forces are balanced
to explain second lower terminal velocity
• opening parachute increases surface area
• opening parachute increases air resistance
• air resistance is greater than weight
• resultant force acts upwards / opposite direction to motion
• parachutist decelerates / slows down
• the lower velocity means a reduced air resistance
air resistance and weight become equal but at a lower (terminal) velocity6
(c) (i) any one from:
• mass of the (modelling) clayaccept size/shape of clay size/amount/volume/shape of clayaccept plasticine for (modelling)clay
• material parachute made fromaccept same (plastic) bag
• number / length of strings1
(ii) Creason only scores if C is chosen
1
smallest (area) so falls fastest (so taking least time)accept quickest/quicker for fastestif A is chosen with the reason given as ‘the largest area so falls slowest’ this gains 1 mark
1[12]
M34.(a) gravitational / gravity / weightdo not accept gravitational potential
1
(b) acceleratingaccept speed / velocity increases
1
the distance between the drops increases1
but the time between the drops is the sameaccept the time between drops is (always) 5 seconds accept the drops fall at the same rate
1
(c) (i) any one from:
• speed / velocity
• (condition of) brakes / road surface / tyres
• weather (conditions)accept specific examples, eg wet / icy roadsaccept mass / weight of car friction is insufficientreference to any factor affecting thinking distance negates this answer
1
(ii) 75 000allow 1 mark for correct substitution, ie 3000 × 25 provided no subsequent step shownor allow 1 mark for an answer 75or allow 2 marks for 75 k(+ incorrect unit), eg 75 kN
2
joules / Jdo not accept jan answer 75 kJ gains 3 marksfor full marks the unit and numerical answer must be consistent
1[8]
M35.(a) gravitational / gravity / weightdo not accept gravitational potential
1
(b) acceleratingaccept speed / velocity increases
1
the distance between the drops increases1
but the time between the drops is the sameaccept the time between drops is (always) 5 seconds accept the drops fall at the same rate
1
(c) (i) any one from:
• speed / velocity
• (condition of) brakes / road surface / tyres
• weather (conditions)accept specific examples, eg wet / icy roadsaccept mass / weight of car friction is insufficientreference to any factor affecting thinking distance negates this answer
1
(ii) 75 000allow 1 mark for correct substitution, ie 3000 × 25 provided no subsequent step shownor allow 1 mark for an answer 75or allow 2 marks for 75 k(+ incorrect unit), eg 75 kN
2
joules / Jdo not accept jan answer 75 kJ gains 3 marksfor full marks the unit and numerical answer must be consistent
1[8]
E3. Paper I3
Good answers calculated the acceleration as 0.25 m/s/s and the power as 200 watts. Weaker candidates in (a) got change in speed over time or 3/12 and gave the answer 4. In (c) many candidates noted the second car was heavier but could not suggest its mass. In (d) very few candidates noted that air resistance increases with speed until it equals the driving force and the bus then travels at a constant speed.
Paper H5
Parts (a) and (b) were correctly answered by an encouragingly large number of candidates, though a minority gained the second mark for a quantitative response in (b).
(c) More able candidates gained full marks for this part of the question, though some lost marks because they used an incorrect value for the acceleration and/or quoted the wrong unit.
(d) This part of the question was poorly done by the majority of even the more able candidates. Answers simply stating that the lorry reaches a top speed or, slightly better, that it reaches a terminal velocity were common. Very few referred to air resistance increasing with speed or attempted to explain the initial acceleration and eventual steady speed in terms of unbalanced and balanced forces respectively.
E4. This question was poorly answered. Some candidates were able to show the relationship between change in speed and time. Even fewer candidates were able to give 40 m/s as the change in speed and arrive at the correct answer of 8 ms-2 . Very few candidates knew the correct units.
Part (b) was poorly answered. Most answers referred to an upwards force. Good answers referred to acceleration due to gravity and resistance due to drag/air resistance which increased with speed leading to balanced forces. In (b)(ii) only a few candidates noted increased
resistance/drag. Incorrect answers referred to the larger surface area of the parachute.
In (c) few candidates knew that the acceleration due to gravity was approximately 10 ms-2 and were unable to get the correct answer 750N.
E5. This recognition item was generally answered well, though not infrequently, joules were thought to be the units of force.
E6. In section (a) many candidates were content simply to calculate the change in momentum from the formula provided, for which simple calculation no credit was available at this level. Only a minority stated that momentum was mass x velocity and/or calculated velocity by dividing change in momentum by mass. Of this minority, fewer still correctly used the mass as 0.05kg.
In (b)(i) most candidates correctly referred to friction with the air, air resistance or drag, though seldom added that this was very great at high speeds. Some candidates simply wrote down all the possibilities they could think of, usually including gravity (which would marginally change the direction of the bullet and increase its speed), presumably in the hope that something they wrote would be correct. The pre-Newtonian notion that things slow down because a force is no longer acting on them was also fairly common.
In (b)(ii) many candidates correctly used the formula ½mv2 though fewer correctly calculated a value for the initial kinetic energy consistent with their answer to part (a). Very few correctly worked the question through, however, and fewer still realised they could proceed directly to the answer via (0.8)2 × 100.
E7. (a) This was generally well answered, although a minority of candidates gave 3 (ie. 6/2) as their answer.
(b) Again, a number of candidates were unable to rearrange F = ma and calculated 9.8/6.
(c) Fully correct and clearly stated responses were surprisingly rare, though most candidates gained some credit by referring to the downwards/(initially) accelerating force of gravity and the opposing air resistance/friction/drag. The increase of the latter with speed until it equalled weight/gravity was mentioned far less often.
E8. The calculation of average speed was well done, but the sketches of the graph were poor for a number of reasons. Too many lines were haphazardly drawn and almost none showed any bend at the top of the bounce, yet the point was usually marked as X2 and it was explained that this was were the ball was stationary. Only about half of the candidates were able to plot the top of the bounce correctly. Many joined the top of the bounce to the point of the bounce by a straight line. The shape of the graph of the falling ball did not appear to have helped candidates.
Although most candidates labelled X1 and X2 correctly, poor English hampered many from gaining marks for points they were unable to write about clearly.
Only the most able candidates were able to calculate the time and distance between bounces.
E9. Foundation Tier
(a) Many candidates found this difficult. The numbers ‘30’, ‘15’ and ‘2’ appeared often but few candidates could work out what to do with them.
(b) Candidates usually gained at least one mark for correctly stating that the bungee jumper ‘goes up’. Few candidates appreciated the significance of the gradient between 4 and 5 seconds and between 5 and 6 seconds, or what had happened when the velocity was zero. Many candidates were unclear about the difference between velocity and acceleration.
Higher Tier
(a) Many candidates produced the correct answer, although the means of achieving the answer was not always clear. it should be remembered that because candidates were asked to show their working, then an incorrectly stated relationship resulted in no marks being awarded, even if the figures were manipulated successfully and produced the correct answer.
(b) Candidates usually gained at least one mark for correctly stating that the bungee jumper ‘goes up’. Few candidates appreciated the significance of the gradient between 4 and 5 seconds, the negative velocity values between 5 and 6 seconds, or what happened when the velocity was zero. Many candidates seemed unable to relate the changes seen in the graph to the sequence of events in the bungee jump.
E10. The majority of candidates knew the correct units for each of the quantities.
E13. Almost all candidates gained marks for parts of this question, few gained all the marks available.
(a) In (i)Y was attributed to weight/gravity by most candidates to gain a mark, far fewer were able to identify X as air resistance/drag/friction. A surprising number did come up with the non-syllabus answer of upthrust. A minority incorrectly identified the forces as a push and a pull. In part (ii)few could explain why X acted in an upward direction. In (iii)X was often given as the bigger force to gain the mark whilst in (iv)a clear statement that the sky-diver would accelerate downwards was far less common.
(b) Many had force X increasing to gain the mark, fewer had force Y staying the same and fewer again the speed staying the same.
(c) Very few candidates failed to gain some marks. Throughout this part errors were carried forward so that a mistake in an early part of the question was only penalised once. In (i)most correctly picked CD, in (ii)and (iii)most had 500 and 50 and went on in (iv)to a correct speed of 10m/s
E14. In part (a) there were few completely correct answers. The idea of resistive forces increasing with speed was often missed. Many did manage to arrive at a point where forward and backward forces were equal and opposite leading to zero net force, zero acceleration and so steady speed. The concept of friction opposing motion was acceptable for one mark, but where mentioned it was sometimes linked to the tyres/wheels, which is the driving force, and so did not gain the mark. The calculations in part (b) were pleasingly well done by the candidates. Some candidates lost the unit work in part (i) with units such as m/s–2. Surprisingly very few candidates applied the principle of ‘conservation of energy’ to answer part (iii) after part (ii).
E16. Part (a) was a good start to the question with the vast majority of candidates scoring marks. In part (b) many candidates did the two calculations correctly and then ran into trouble with explaining the top speed of a car. Candidates did not appear to be familiar with the syllabus statements on this topic.
E17. Parts (a) and (b) were quite well answered, the main loss of marks being due to unit errors or omissions. Part (c) was not well answered and there was little evidence of candidates being familiar with the syllabus statements on this topic.
E18. In part (a) many candidates were unaware that an object can continue at a constant speed if opposing forces are balanced, and that a straight line graph of proportionality would result. In part (b) only a minority of candidates knew the definition of acceleration. In part (c), most candidates identified trolley C as having the smallest acceleration but many candidates did not correctly link the greater mass as being the cause for the smallest acceleration. Candidates need reminding that imprecise answers such as ‘because it’s got more stuff in it’ are not acceptable.
E19. The graph in part (a)(i) was well approached. Most candidates chose sensible scales, and there were only occasional errors in plotting. There were still a significant number of dot-to-dot lines drawn. Answers to part (a)(ii) were often imprecise, a common reason being ‘strong correlation’ and other statements sounding pertinent. Reference to the line being straight and through the origin were less frequent. In part (a)(iii) many candidates calculated 490 Id correctly, and many went on to use this information to obtain the braking distance. Some candidates failed to show how they had obtained their answer and so were unable to score credit if the answer was outside tolerance. Part (a)(iv) was generally correct but there were two types of answer which did not score. Firstly there were many answers like ‘mass’ or ‘friction’ which did not speci1_ whether it was greater or smaller to increase the braking distance. Secondly there were answers relating to the driver, commonly with reference to alcohol or drugs. Parts (b)(i) and (b)(ii) were generally correct. In part (b)(iii) the better candidates often made a comment about smaller deceleration but then failed to relate this to a reduced force on the car or passengers. Some candidates tried to explain how the crumple zone absorbs the energy but rarely in a credit worthy manner.
E20. This question was not well answered. Most answers showed a clear lack of understanding in pan (a) and only a few candidates referred correctly to differences in air resistance. In (b) more candidates were successful but too many linked gravity with vacuum. Common answers included ‘they will weigh the same in a vacuum’ and ‘there’s no gravity in a vacuum’.
E21. This question was well answered. However, it was disappointing that a substantial minority of candidates could not recall the equations correctly or complete a calculation without error even when they had written the equation. A common error in part (a)(ii) was to leave the speed in km/s rather than converting to mis. Most candidates had the right idea in part (a)(iii), but not all were specific enough to gain credit. In part (b)(ii) many candidates were able to work out the deceleration For those that did not, a common error was to use the orbital speed in the
calculation. A number of candidates either omitted, or did not know, the correct unit for acceleration. In part (c)(ii) most candidates who had previously calculated the correct deceleration went on to calculate the correct force. A number of candidates failed to make the link between parts (b) and (c) and in the absence of any stated value for acceleration chose to use 10 m/s2.
E22. This question was generally well answered but most candidates managed to get at least one part of (b) wrong. Very few candidates realised that force X would stay the same in part (b)(iv). In part (c) many candidates failed to make a link between area and force Y.
E23. Although in part (a) the stem of the question clearly stated that the motorbike was moving, and the artwork reinforced this image of movement, many candidates incorrectly stated that the motorbike would be stationary. This was often followed by a statement that the motorbike would go backwards. In part (b) few candidates were able to recall the equation for acceleration or the correct unit. There were very few correct calculations. In part (c) most candidates were able to describe and explain what would happen to a car braking on an icy road and also give factors that could cause stopping distance to increase. However a number of candidates used imprecise language which meant that answers could not gain credit.
E24. (a) There were many mistakes in this part of the question and almost total lack of understanding in part (b). The word ‘acceleration’ made only rare appearances and the link between it and resultant force seemed a mystery to all but a few candidates.
(b) In part (b)(ii) many candidates managed to suppress their common sense model of the skydiver in favour of answers which suggested the skydiver was hovering motionless in mid air.
E25. (a) (i) Most candidates were able to use the data and equation provided to produce a numerical value for the weight of the toy but there were few responses which stated the correct unit.
(ii) Most of the candidates were aware that the forces involved would need to be balanced to enable the toy to hover.
(b) (i) Most candidates were able to explain the term ‘acceleration’ however, there were many references to ‘move’, ‘increase’ etc without any elaboration.
(ii) This was question was generally answered correctly however, there were a number of incorrect references to ‘south’.
(iii) Half of the candidates understood that the momentum would increase but few could give a valid reason why.
E26. (a) Most candidates were aware that the stopping distance of 53 metres could be found by adding the thinking distance and the braking distance. However, a significant number of responses were noted where the candidates had multiplied the figures together, producing a stopping distance of 570 metres. Candidates with this answer did not seem to appreciate that this was an unrealistic value.
(b) (i) There were some excellent attempts at good quality curves. However, significant numbers of candidates were careless, did not start at (0, 0) and many had lines below the original curve, or cutting through it.
(ii) The majority of candidates scored both marks with few candidates unable to score at least one mark.
(c) (i) The vast majority of candidates were able to correctly match the conditions to the graph lines.
(ii) Many candidates achieved credit by identifying that the data for Driver C was derived from the adverse effects of two conditions and that further tests would be required to determine the relative effects of either condition to the driver’s reaction time.
E27. (a) (i) There were very few correct answers. Many candidates said it was the accelerating force, but ignored that it may equal zero.
(ii) A very common error here was to suggest that a zero resultant force meant that the plane was stationary (despite the question stating that the plane was moving).
(b) To gain full marks here, candidates had to rearrange the equation and substitute the correct values – remembering to convert kN into newtons, and to include the effect of all 4 engines. They also had to quote the correct units. Each of these tasks provided a substantial number of errors and only the better candidates did everything correctly.
(c) This question was poorly answered with the majority of candidates scoring no marks.
Candidates stating that the “resultant” force was increased as the plane gained speed.
While the idea of forces acting against motion was appreciated, few tried to explain that these increased with an increase in speed. Many candidates thought the plane was lifting into the air and answered in terms of ‘because it is lifting off the ground, it doesn’t need to accelerate’.
E28. (a) This was well answered, the favourite wrong answers were: gravitational potential energy and mass.
(b) (i) In general physics terms the idea of balanced and unbalanced forces seemed to be quite well understood. However candidates often missed the first mark by talking about gravity / weight/ L accelerating the ball-bearing with no reference to Force M. The idea that Force M increases with the speed of the ball-bearing was understood. A few candidates said that L reduced with time. Too many candidates lost the last mark by stating ‘the forces start to balance / equal out / equal without stating that when the ball falls at constant speed, Force L = Force M. A reasonable number of better answers talked about zero resultant force.These better responses often included correct statements about the resultant force at the various stages in the fall, as well as higher level descriptions of how the acceleration starts off large and reduces to zero.
(ii) Surprisingly only just over half the candidates could give the correct answer. Afrequent incorrect response was ‘optimum speed’.
(iii) There were many well presented calculations using data correctly drawn from the graph. Most wrong answers were due to candidates not realising the need to use the straight line part of the graph. A smaller number of candidates obtained a wrong answer because they took values from a single point on the graph. Too few candidates (even when giving the correct answer) showed how they obtained the values used. Quite a number of candidates failed to read the scale on the graph correctly and subsequently calculated the wrong answer.
E31. (a) Many candidates were able to perform the calculation correctly but few candidates were able to supply the correct unit. There were many instances where the candidates substituted 1.2 m/s 2 into the equation and then went on to either use 1.22 or 1.2 × 2 in their calculation.
(b) (i) It was disappointing that very few candidates gave the correct answer to this question, the majority of the incorrect answers being mass, acceleration, momentum and time.
(ii) Again there were very few correct answers. Most candidates thought that the use of a line graph was to improve the presentational appearance of the data and to make
the data easier to understand.
(iii) Most candidates scored at least 2 marks, generally for choosing C and then stating that the forces were equal or the arrows were the same length.
A significant minority of candidates chose B because the resultant force forwards would be the greatest so the cyclist would be going the fastest ie, 9 m/s.
E32. (a) This question was well done with nearly all of the students scoring both marks.
(b) This question was not well answered for a variety of reasons. Some students simply did not know where to start, whilst others tried using momentum. Also, many realised the need to use the equation for kinetic energy, but were then unable to transform it or failed to square root; 300 was a common incorrect answer. Few students stated that GPE = KE although they used their answer from part (a) in the calculation. Only a tenth of students were able to complete the calculation and give an answer with an appropriate number of significant figures.
(c) Most students scored one mark for mentioning friction, but very few students were able to give a complete explanation to score all three marks. The idea that work would be done against friction was hardly ever mentioned. A significant number of students thought that the reduced maximum speed was due to the change in angle of the slide and the slide becoming horizontal.
E33. (a) Most students achieved two marks by calculating the correct numerical value. Less than a fifth of students scored the third mark by stating the correct unit; the most common error was to state that the weight was measured in kilograms.
(b) This was the Quality of Written Communication (QWC) question on the paper which required the students to demonstrate their ability to use good English, organise their information clearly and use specialist terms where appropriate. Many students were able to supply some basic information as physics points, but often their responses lacked either the structure and organisation or the logical sequencing to achieve Level 2 and score three or four marks.
(c) (i) This question was answered well. The main errors were the height at which the parachute was dropped (which was in the stem of the question,) or to state the dependent variable.
(ii) Of the three parachutes illustrated, the correct choice of parachute C was made by the vast majority of students, but there was less success in giving the reason in
terms of a comparison of the relative surface areas and relative rates of descent.
E34.(a) Most students gave a correct answer. The only common incorrect responses seen were gravitational potential and gravitational potential energy.
(b) This was well answered with most students gaining at least two marks. Most students identified that the car was accelerating and that the distance between the oil drops was increasing. Fewer students appreciated that the oil drops falling at regular time intervals was also relevant to confirming that the speed was increasing.
(c) (i) Over half of the students gave a relevant factor. Students failing to gain the mark usually gave thinking time / distance or a factor that affects thinking distance.
(ii) Very few students were able to complete all the steps required in order to gain all three marks. Many students failed to change the 3 kN value to 3000 N, but some of these students went on to give an answer of 75 with the unit kJ and so did score full marks. However it was more common for the answer 75 to have no unit attached or an incorrect one, N/m being common.
E35.(a) Most students gave a correct answer. The only common incorrect responses seen were gravitational potential and gravitational potential energy.
(b) This was well answered with most students gaining at least two marks. Most students identified that the car was accelerating and that the distance between the oil drops was increasing. Fewer students appreciated that the oil drops falling at regular time intervals was also relevant to confirming that the speed was increasing.
(c) (i) Over half of the students gave a relevant factor. Students failing to gain the mark usually gave thinking time / distance or a factor that affects thinking distance.
(ii) Very few students were able to complete all the steps required in order to gain all three marks. Many students failed to change the 3 kN value to 3000 N, but some of these students went on to give an answer of 75 with the unit kJ and so did score full marks. However it was more common for the answer 75 to have no unit attached or an incorrect one, N/m being common.
