U7WS3 Impulse = Change in Momentum (One object) Name:______

1. a) What is the momentum of a 5000. kg truck moving at 25 m/s?

b) What is the momentum of a 5000. kg truck at rest?

c) Could a 2000 kg car have the same momentum as the truck in question 1A? Explain.

2. a) Who has more momentum, a 70 kg person running at -2 m/s or a 50 kg person running at +3 m/s?

b). If each person stops, who has a greater change in momentum? Show work.

d) What was the impulse experienced by each person?

3. a) A 5 kg runaway wombat named Wally speeds up from 2 m/s to 8 m/s. What is his change in momentum? What impulse did he experience?

b) Wally the Wombat gets tired and slows from 8 m/s to 2 m/s. What is his change in momentum?

c.) Now Wally the Wombat, initially running at 8 m/s slows to a stop and turns around running the other direction at 2 m/s. What is his change in momentum? What impulse did he experience?

4. A 0.1 kg ball is thrown at your arm and the ball bounces off. A 0.1 kg lump of clay is thrown at your arm and the clay sticks. a) Does the ball or the clay experience a bigger change in momentum? Which object experienced a bigger impulse?

b) Assuming each object is in contact with your arm for 0.2 seconds, which object would hurt more? Why? 5. Two identical twin ferrets are racing through the living room at the same speed. Freddy the Ferret skids to a stop in 2 seconds while Frieda the ferret takes 1 second to stop.

a) Who has a greater change in momentum? Who experienced a bigger impulse?

b) Who experienced a bigger net force while stopping?

6. a) A pitcher throws a 100 g ball at +25 m/s at the catcher’s mit stops it in 0.1 seconds. How big is the net force exerted by the mit on the ball? How big is the impulse?

b) Mr. Dominic’s evil twin Dominique uses a butterfly net to catch the same ball in part (a). The net stops it in 1.0 second. How big is the net force exerted by the mit on the ball? How big is the impulse?

7. If you jump off a roof and land with your knees locked, why does this hurt more than when you bend your knees while landing?

8. Modern cars are designed so that a minor accident causes the auto body to crumple and/or fly apart. Is this just a ploy by the auto repair industry to make money or is there a physical reason to do this? Explain.

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