A plunger of mass m rests on a spring with constant k. The spring is pressed down a distance x and released from rest. How large does the the mass need to be in order to keep the plunger in contact with the spring?
The Attempt at a Solution
Using the Conservation of energy equation and solving for m, I get:
kx2/(2gh+vf2) = m
I have a suspicion that I somehow have to incorporate the second equation into the answer, but am stumped as to how I proceed.