TEMPAT BELAJAR INFINITE Rukan Taman Meruya Blok M no. 75 Meruya Ilir Jakarta Barat (021) 587-3955

1. Potter, who has a mass of 50 kg, height of 1.54 m, is able to run a distance of 1 km in a time of 5 min 12 s. his average speed was calculated to be 3.21 m/s. Write down all the physical quantities and their respective SI units for the situation above.

2. The current in the wire is due to electrons, each with charge q, that move with speed v along the wire. There are n of these electrons per unit volume. For a wire having a cross-sectional area S, the current I is given by the equation I = nSqv k,where k is a constant.i) State the units of I, n, S, q and v in terms of the base unitsii) By considering the homogeneity of the equation, determine the value of k.

3. A cylinder of length L has a circular cross-section of radius R, as shown in Fig. 1.1.

The volume V of the cylinder is given by the expression V = R2L .The volume and length of the cylinder are measured as V = 15.0 ± 0.5 cm3, L = 20.0 ± 0.1 cm. Calculate the radius of the cylinder, with its uncertainty.

4. Perform the following calculation giving your answer to the correct number of significant figures. a. 2001 in scientific notation is:b. 0.00345 in scientific notation is:c. Express 3.14159 in 4 significant figures:d. 37.76 + 3.907 + 226.4e. 319.15 - 32.614f. (5.5)3

g.12.2× 8.0 ×0.001

2.5

5. In each case below, resolve the vector into two perpendicular components in the x and y directions.a b

6. Two forces of magnitude 6.0 N and 8.0 N act at a point P. Both forces act away from point P and the angle between them is 40°. Determine the magnitude of the resultant of the two forces.

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θ

20 N

15 N

10N

0.5 m

3.0 m

TEMPAT BELAJAR INFINITE Rukan Taman Meruya Blok M no. 75 Meruya Ilir Jakarta Barat (021) 587-3955

7. The object in the diagram is in equilibrium. What is the magnitude of the resultan force acting on the object? (θ = 30o)

8. A man of weight 600 N stands at the end of a uniform wooden plank, which is pivoted as shown in the diagram. What is the weight of the wooden plank?

9. The diagram shows a uniform beam of length 1.5 m and weight 60 N resting horizontally on two supports.

a By taking moments about the support A, determine the force RB at the support B.b Use your answer to a to calculate the force RA at support A.

10. A gardener pulls a 50 kg roller along level ground, as shown in the diagram.The roller moves at a steady speed along the level ground when the handle makes an angle of 30° to the horizontal ground and the gardener pulls with a force of 300 N along the handle.

a Calculate the horizontal component of the force 300 N. b. Determine the vertical contact force acting on the roller due to the ground.

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TEMPAT BELAJAR INFINITE Rukan Taman Meruya Blok M no. 75 Meruya Ilir Jakarta Barat (021) 587-3955

11. Cannons are being fired in a mock battle scene. The spectators are at a safe distance of 600 m from the cannons. Calculate how long it would take for the sound from the cannons to reach the spectators. (Speed of sound in air = 340 m s−1.)

12. The displacement–time graph for an object is shown below.

a What does the gradient of a displacement–time graph represent?b Describe the journey of the object.c Calculate the velocity of the object at 2.0 s.

13. A cyclist travels a distance of 3.2 km in 15 minutes. She rests for 30 minutes. She then covers a further distance of 6.2 km in a time of 40 minutes. Calculate the average speed of the cyclist in m s−1:a for the first 15 minutes of the journeyb for the total journey.

14. Diagram shows the horizontal forces acting on a motorbike and its rider travelling along a level road. The total mass of the rider and the motorbike is 160 kg. Determine the acceleration of the motorbike.

15. The diagram shows the horizontal forces acting on a 920 kg car.

The total forward force acting on the car is 400 N. The drag on the car depends on its speed v and is given by the expression: drag 0.3v2 N.At a particular instant the car is travelling at a speed of 20 m s−1. Calculate:i the net force on the carii the acceleration of the car.

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TEMPAT BELAJAR INFINITE Rukan Taman Meruya Blok M no. 75 Meruya Ilir Jakarta Barat (021) 587-3955

16. The diagram shows an 80 kg person in a lift.

The normal contact force acting on the person from the base of the lift is R. Determine the magnitude of R when the lift:a is travelling upwards at a constant velocity of 2.0 m s−1 b is accelerated upwards at 2.3 m s−2.

17. A child of mass 35 kg on a swing is pulled to one side.The diagram shows the forces acting on the seat of the swing when it is in equilibrium.a What is the net force on the seat?b Draw a triangle of forces. Hence determine:

i the tension T in the ropeii the angle made by the rope with the vertical.

18. An object A of mass 2.0 kg is connected to object B is placed on a rough horizontal surface and A is suspended freely, as shown in figure 2.78 the pulley can be considered frictionless. A is allowed to fall from rest. A constant friction force of 5.0 N acts on B as it moves. Determine a) The acceleration of the object b) The tension in the string

19. Two blocks, weighing 250N and 350 N, respectively, are connected by a string that passes over a massless pulley as shown. The tension in the string is:

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TEMPAT BELAJAR INFINITE Rukan Taman Meruya Blok M no. 75 Meruya Ilir Jakarta Barat (021) 587-3955

20. A 5.0-kg crate is resting on a horizontal plank. The coefficient of static friction is 0.50 and the coefficient of kinetic friction is 0.40. After one end of the plank is raised so the plank makesan angle of 30◦ with the horizontal, what is the force of friction?

21. The diagram shows a stone tied to the end of a length of string. It is whirled round in a horizontal circle of radius 80 cm.

The stone has a mass of 90 g and it completes 10 revolutions in a time of 8.2 s.Calculate:i the time taken for one revolutionii the distance travelled by the stone during one revolution (this distance is equal to the

circumference of the circle)iii the speed of the stone as it travels in the circleiv the centripetal acceleration of the stone

v the centripetal force on the stone.

22. An aeroplane is circling in the sky at a speed of 150 m s−1. The aeroplane describes a circle of radius 20 km. For a passenger of mass 80 kg inside this aeroplane, calculate:a her angular velocityb her centripetal accelerationc the centripetal force acting on her.

23. A stone of mass 120 g is fixed to one end of a light rigid rod.

The stone is whirled at a constant speed of 4.0 m s−1 in a vertical circle of radius 80 cm.

Calculate the ratio:

tension in the rod at Atension in the rod at B

24. Refer to figure 3.29. An object, at A, moves with an initial speed of 2.5 m s−1 and stops at B. determine the height H.

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TEMPAT BELAJAR INFINITE Rukan Taman Meruya Blok M no. 75 Meruya Ilir Jakarta Barat (021) 587-3955

25. The diagram shows a child on a swing. The mass of the child is 35 kg. The child is raised to point A and then released. She swings downwards through point B.

a Calculate the change in gravitational potential energy of the child between A and B.b Assuming that air resistance is negligible, calculate the speed of the child as she

passes through the equilibrium position B.

26. A stunt person slides down a cable that is attached between a tall building and the ground.

The stunt person has a mass of 85 kg. The speed of the person when reaching the ground is 20 m s−1. Calculate:a the change in gravitational potential energy of the personb the final kinetic energy of the personc the work done against frictiond the average friction acting on the person.

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