Two blocks (m=1.0 kg and M=10 kg) and a string (k=200 N/m) are arranged on a horizontal, frictionless surface (in the picture m rests atop M). The coefficient of static friction between the two blocks is .40. What amplitude of simple harmonic motion of the spring-blocks system puts the smaller block on the verge of slipping over the larger block? acom=F/(mA+mB) F=-kAcos(ωt) and ω=√(k/(mA+mB)= 4.26 so F=-200Acos(4.26t) acom=-200Acos(4.26t)/11 =-18.2Acos(4.26t) This is all I got so far. What I am confused about is that μk is not given. So isn't it impossible to figure out the acceleration of the top block once static friction is overcome? I also am not given the lengths of the blocks.