Peoples Physics Book Version-2

(Marvins-Underground-K-12) #1

8.6. Momentum Conservation Problem Set http://www.ck12.org


i. From this data predict the impact position of the other ball.
ii. One of the lab groups declares that the data on the floor alone demonstrate to a 2% accuracy that the
collision was elastic. Show their reasoning.
iii. Another lab group says they can’t make that determination without knowing the velocity the balls
have on impact. They ask for a timer. The instructor says you don’t need one; use your meter stick.
Explain.
iv. Design an experiment to prove momentum conservation with balls of different masses, giving
apparatus, procedure and design. Give some sample numbers.

Answers to Selected Problems


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8. 37.5 m/s
9.v 1 = 2 v 2
10. a. 24kg− 5 mb. 0.364 m/s c. 22kg− 5 md. 109 N e. 109 N due to Newton’s third law
11. 2.0 kg,125 m/s
12. 21 m/s to the left
13. 3250 N
14. a. 90 sec b. 1. 7 × 105 sec
15. a. 60 m/s b..700 sec c. yes, 8.16 m
16. 0.13 m/s to the left
17. a. 11000 N to the left b. tree experienced same average force of 11000 N but to the right c. 2500 lb. d. about
2 .5 “g”s of acceleration
18. a. no change b. the last two cars
19. a. 0.00912 s

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