A box of mass M is suspended by a spring of stiffness k. A small block of mass m is placed inside the box. If the system is pulled downward by a distance d and then released from rest:
a.) find the force between the bottom of the box and the block as a function of time;
b.) for what value of d does the block just begin to leave the bottom of the box at the top of the vertical osscilations?
The Attempt at a Solution
I'm unsure of how to proceed to determine the force of reaction from the equations above that i've worked out.