1) The diagram shows the masses and velocities of two trolleys about to collide.

After the impact they move off together. What is the total kinetic energy of the trolleys after the collision?

2) A body, initially at rest, explodes into two fragments of masses M and 3M having total kinetic energy E. The kinetic energy of the fragment of mass M after the explosion is

3) Two trolleys are placed together on a horizontal runway with a compressed spring between them.

When they are released, the 2.0 kg trolley moves to the left at 2.0 m s^–1. How much energy was stored in the spring?

4) A 2.0 kg object moving at 10 m s^–1 collides normally with a wall and bounces off with half of its original kinetic energy. What is the magnitude of the impulse applied by the wall?

5) A tennis ball of mass 100 g is struck by a tennis racket. The velocity of the ball is changed as shown.

What is the magnitude of the change in momentum of the ball?