P2a Revision Questions F ( Part 2 )

1. Below is some data about a rocket powered car. A test is done where it accelerates from rest on a 200 m track.

Mass of car = 1,400 kg Length of track = 200 m Thrust force = 20,000N Speed at the end of the track = 50 m/s Time to cover 200 m = 8 seconds

a) What is the cars acceleration?

b) How much work does the rocket engine do?

c) Why is the kinetic energy of the car less than the work done by the rocket engine?

d) At the end of the track the car brakes and comes to rest. What will happen to its kinetic energy?

e) What could be added to the car to help it slow down quickly?

2. Below is a picture of a crossbow loaded with a bolt.

To load the bow the string is pulled back 0.3 m with a force of 200N a) How much work is done loading the crossbow? b) What kind of energy does the bow store? c) What happens to this energy when the trigger is pulled? d) If a heavier bolt is used will it travel at the same speed? Explain your answer.