1. The problem statement, all variables and given/known data A boy has stacked two blocks on the floor so that a 5.0 kg block is on top of a 2.0 kg block. 1. If the coefficient of static friction between the two blocks is 0.40, and the coefficient of static friction between the bottom block and the floor is 0.22, with what force horizontal should the boy push on the upper block to make both blocks in the system start to slide along the floor. 2. If he pushes too hard, the top block starts to slide off the lower block. What is the maximum force with which he can push without that happening? 2. Relevant equations Fs = micro(s) * N 3. The attempt at a solution 1. Fs (between 2 blocks) = 0.40 * (5+2) * 9.8 = 27.44 N Fs (between bottom block and the floor) = 0.22 * 2 * 9.8 = 4.312 Fnet = 27.44 + 4.312 = 31.752 N => wrong answer 2. Fs (maximum) = 27.44 N => wrong answer Please help! Thanks!