My physics class is intro more or less (it's calc based; 111 NOT 101). I'm a bit confused when it comes to springs..specifically, finding the maximum compression a spring will have. Here are the given variables in a problem in my textbook: *spring has negligible mass *force constant(k) = 1600n/m *spring is placed virtically with one end on the floor *1.2kg book is dropped from a height of .80m above the top of the spring maximum distance the spring will be compressed? what confuses me specifically are the signs (+/-) and the distances involved. Here is what I am thinking: I need to use K1 + U1 = K2 + U2 (k1 = zero) now when it comes to potential energy, i don't know whether to use MGY or 1/2kx^2..can someone point me in the right direction? thanks!