A block of mass m is attached to a horizontal spring with constant k. resting on top of this block is another block of mass m. a coefficient of static friction mu exists between the two blocks. now suppose the spring is initially at equilibrium length, and someone gives it a push. the block moves in SHM in response. At a certain distance from equilibrium, the top block starts wo slide off the bottom one, find the x in terms of the given quantities and g. So with the the moment when the top block slides off the block is when umg=ma? and where do I go from here?