Assignment:
An 80kg man jumps from a height of 2.5m onto a platform mounted on springs. The spring compress 0.240 below its initial position and then it rebounds. Platform & spring have negligible mass.
a) What is the spring's force constant?
b) What is his speed when the spring is compressed 0.120m?
c) If he gently steps on the platform, how far would he push it down?