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Author Question: A railroad freight car, mass 15 000 kg, is allowed to coast along a level track at a speed of 3.0 ... (Read 62 times)

jeatrice

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  • Posts: 543
on: Jul 28, 2018
A railroad freight car, mass 15 000 kg, is allowed to coast along a level track at a speed of 3.0 m/s. It collides and couples with a 54 000-kg loaded second car, initially at rest and with brakes released. What percentage of the initial kinetic energy of the 15 000-kg car is preserved in the two-coupled cars after collision?
 a. 78
  b. 22
  c. 18
  d. 38
  e. 14

Question 2

A 22.3-g bullet moving at 1 000 m/s is fired through a one-kg block of wood emerging at a speed of 100 m/s. What is the change in the kinetic energy of the bullet-block system as a result of the collision assuming the block is free to move?
 a. 0 J
  b. 10.8 kJ
  c. 10.8 kJ
  d. 11.2 J
  e. 223 J


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bookworm410

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Reply #1 on: Jul 28, 2018
Answer to Question 1

b

Answer to Question 2

c


jeatrice

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  • Posts: 543
Reply 2 on: Jul 28, 2018
Excellent

softEldritch

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Reply 3 on: Yesterday
Thanks for the timely response, appreciate it

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