1. A 1 kg block is on a flat frictionless surface. Attached to a relaxed spring (k=50N/m). A light string is attached to the block and runs over a frictionleas pulley to a .45kg dangling mass. If the dangling mass is released from rest, how far will if fall before stopping? 2. Relevant equations U= 1/2kx^2 F=-kx W=Fd w=mg (I'm not exactly sure which ones I do/don't need) 3. The attempt at a solution: I really have no idea where to begin. The answer the book gives is .176m.