1. The problem statement, all variables and given/known data A slab of mass m1 = 18 kg rests on a frictionless floor, and a block of mass m2 = 12 kg rests on top of the slab. Between block and slab, the coefficient of static friction is 0.30, and the coefficient of kinetic friction is 0.20. A horizontal force ,F of magnitude 58 N begins to pull directly on the block. What are the accelerations of (a) the block and (b) the slab? 2. Relevant equations 3. The attempt at a solution Attempts for (a) m1*a= F - fk Solved for a. I got it right. Attempts for (b) It's sliding (F > Fs) and there is no friction between floor and the slab. I assumed the fk is pulling the slab. I put it in this way : m2*a = fk. Solved for a. But my answer is wrong. fk = magnitude of kinetic friction between block and slab. I would guess the equation for my (b) or my assumption is wrong.