Select all the factors that influence the amount of elastic energy an object has. Compression

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Question 1 options:

Aboxcar traveling at 12 m/s approaches a string of 5 identical boxcars sitting stationary on the track. the moving boxcar collides and links with the stationary cars and they all move off together along the track. what is the final speed of the cars immediately after the collision? (you may take the mass of each boxcar to be 18,537 kg.)

Could someone me find the answer to this problem.

Abowling ball rolling down the lane toward the pins has gravitational potential energy. a. no b. a lot of c. a little