Impulse, Momentum and Conservation of Momentum

1. A 60 gram ball is hit with a stick and given a velocity of 75 m/s. If the stick exerted an average force of 3E4 N, what was the time of impact between the stick and the ball?

2. A running back, weighing 900N and moving at 2 m/s, is stopped in 0.70 seconds when hit by another player.

a. What average force did the player exert on the running back?

b. How much did the running back’s momentum change?

3. Identical twins, each weighing 500 N, are riding in a car traveling at 20 m/s. One of the girls is wearing a seat belt and the other is not (bad girl). The car is in an accident where the girl wearing the seat belt is brought to a rest in 0.120 seconds and the dashboard brings the other girl to a stop in only 0.0080 seconds.

a. What is the impulse each girl experiences?

b. What is the force exerted on each girl?

4. A rocket weighing 1.2E5N experiences an upward thrust of 2E5 N for about 1.5 minutes during take off.

a. What is the impulse exerted on the rocket?

b. What is the velocity of the rocket at the end of the 1.5 minute period?

5. A bowling ball of mass 8 kg is moving at 10 m/s when it strikes a 1.5 kg pin. After being hit, the pin flies backward (in the same direction that the ball was traveling) at 20 m/s while the ball continues in the same direction. What is the speed of the ball after impact?

6. A less than intelligent inventor designs a very lightweight gun that shoots heavy bullets. The 50 N bullet leaves the 40 N gun with a velocity of 200m/s. What is the recoil velocity of the gun?

7. A loaded freight car of mass 5000 kg breaks away and moves down the track with a speed of 4 m/s. It collides with two stationary cars of mass 1500 kg each. If they all couple together, what speed do they move down the track?

8. An ice-hockey player who weighs 900 N is skating with a velocity of 8 m/s when he slams into a member of the opposing team who is standing still. They become tangled together and move down the ice with a velocity of 5m/s. What is the weight of the other player?