A body with a mass of 2 kg is released from rest a height of 0.4m above the edge of a vertical rested spring with k= 1960 N/m. Assume there is no energy loss in the collision: 1. what's the maximal contraction of the spring? 2. to what height will the body reach back? about 2 - Because I have energy coservation it seems reasonble that the body will reach the same height it was released from right? but... in 1 I found that the maximal contraction with respect to the loose length of the spring is 0.1 m and that it's maximal extension with respect to the loose length is -0.08 m... so it seems that when the spring is at full strech upwards - it's still lower than the initial height of 0.4 m above the loose length of the spring... so how does it all add up? does it have anything to do with the fact that maybe the body doesn't stay attached to the spring? if it doesn't stay attached - how can I know what's the point where it is released from the spring in its way up?