What is the difference between the energy of spring a, stretched 0.6 meters, and spring b, stretched 0.3 meters, if they have the same spring constant?

28. evolution

29. environment, survive, offspring  

explanation:

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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