Block A of mass 5 kg is on a horizontal rough table with μ = 0.8 and is connected over a pulley to a hanging 4 kg block B. A horizontal force of 50 N pulls A to the left. Find the acceleration and the friction force on A.

Question

G1 Physics · Accepted Answer

If the system is static, T = 4g = 40 N. The 5 kg block then needs only 50-40 = 10 N friction to the right. Maximum static friction is 0.8×5×10 = 40 N, so equilibrium is possible. Therefore a=0 and friction is 10 N to the right.