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?
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.