Example 6: A car starts from rest and accelerates at 7m/s2. (a) Find the velocity of the car after 3s.(b) What is the displacement of the car during these 3s?(c) Suppose that after 3s the driver hits the breaks with a deceleration of 5m/s2. What is the stopping distance of the car?

Example 7: A jet plane lands with a speed of 100 m/s and can accelerate at a maximum rate of -5.00 m/s2 as it comes to rest. (a) From the instant the plane touches the runway, what is the minimum time interval needed before it can come to rest? (b) Can this plane land on a small tropical island airport where the runway is 0.800 km long?

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Example 8: A stone is released from the roof a 50m tall building. How long will it take to hit the ground?

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Example 9: A stone is thrown upwards with an initial velocity of 30m/s.

(a) What is the maximum height the stone will reach?

(b) How long does it take for the stone to return back?

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Example 10: Find the velocity of the particle describedin figure at the following times: (a) t = 1.0 s, (b) t =3.0 s, (c) t = 4.5 s, and (d) t= 7.5 s.

Example 11: The diagram below shows the velocity v of a moving body on a straight line.

(a) Find the acceleration of the body in each time-interval below: (i)0-3s, (ii) 3s-5s , (iii) 5s-9s

(b) Find the total displacement(c) Find the total distance travelled(d) Find the average velocity and average speed of the body between 0

and 9s.

1.7 ProblemsExercise1: A stone is thrown vertically upwards with a speed of 12m/s from the edge of a cliff 70.0m high. (a) How much later does it reach the bottom of the cliff? (b) What is the speed just before hitting the bottom of the cliff? What total distance did it travel?

Exercise2: A motorist drives along a straight road at a constant speed of 15.0 m/s. Just as she passes a parked motorcycle police officer, the officer starts to accelerate at 2.00 m/s2 to overtake her. Assuming the officer maintains this acceleration, (a) determine the time it takes the police officer to reach the motorist. Find (b) the speed and (c) the total displacement of the officer as he overtakes the motorist. (d) On a single graph sketch position-time and velocity-time graphs for the motion of the motorist and the officer.

Exercise 3: The driver of an automobile traveling at 30m/s perceives an obstacle on the road and slams on the brakes. Assume that there is a reaction time of 0.2s and that the deceleration of the automobile is 4m/s2. (a) Sketch the velocity of the automobile against time . (b) Use your sketch, or otherwise, to calculate the total stopping distance of the automobile.

Exercise 4:A bus starts from rest and moves with constant acceleration of 1m/s2 for 8s. It then moves with the acquired speed for 22s and thenaccelerates for 5s with constant acceleration of 2m/s2. Finally decelerates with 4m/s2 until it comes at rest. (a) Sketch the diagram of the speed of the bus versus time, (b) Use your diagram, or otherwise, to find the total distance traveled by the bus. (c) Calculate the average speed of the bus during this journey.