Chapter 9 Review
1. What are two ways you can increase the amount of impulse on a stopping object.
2. In terms of impulse, how does an air bag reduce injuries that would be caused by the steering wheel during an accident.
3. Ashley and Timothy run towards each other and collide. Describe what would happen if their speeds were equal but opposite. What would happen if Timothy was standing still and Ashley ran into him?
4. What is the momentum of a 145 g baseball traveling at +40.0 m/s? 5.80 kg m/s
5. What impulse is needed to stop a 45 g mass traveling at a velocity of -42 m/s? 1.89 kg m/s
6. A force with a magnitude of 540 N is used to stop an object with a mass of 65 kg moving at a velocity of +175 m/s. How long will it take to bring the object to a full stop? 21 s
7. In hitting a stationary hockey puck having a mass of 180 g, a hockey player gives the puck an impulse of 6.0 N*s. At what speed will the puck move toward the goal? 33 m/s
8. A metal sphere with a mass of 80.0g rolls along a frictionless surface at 20.0 m/s and strikes a stationary sphere having a mass of 200.0 g. The first sphere stops completely. At what speed does the second sphere move away from the point of impact? 8.00 m/s
9. A snowball with a mass of 85 g hits a snowman’s top hat and sticks to it. The hat and the snowball, with a combined mass of 250g, fall off together at 6.5 m/s. How fast was the snowball moving at the moment of impact? 19 m/s
10. Explain how a motorcycle can have the same linear momentum as an automobile.
11. Why does a fire hose recoil when the water is turned on?
12. Suppose you were an astronaut drifting in space several meters from your spacecraft. The only thing you have with you is a sack filled with moon rocks. How could you return to your ship?
13. A sphere of mass 5.00 kg moving at 4.00 m/s collides with an identical sphere that is at rest. The first sphere moves off at an angle of 60.0 degrees to the left of its original path, and the second sphere moves off in a direction 90.0 degrees to the right of the first sphere’s final path. What are the speeds of the two spheres as they separate? Assume frictionless conditions. 2.00 m/s & 3.46 m/s
14. Chris is running north at 2.3 m/s. He runs into Becca who is walking east at 1.1 m/s. Afterwards they become entangled. If Chris has a mass of 91 kg and Becca has a mass of 72 kg, what is their velocity (magnitude and direction) after the collision? 1.4 m/s at 21° E of N (or 69° N of E)