Question

Block A with mass m is placed on a block B with mass M (Figure 1). The coefficient of static friction between the two blocks surfaces is mu_s. Block B is on a frictionless, horizontal surface. Find the minimal horizontal force F rightarrow necessary to be applied to block B to make block A starting sliding on block B. Include the free-body diagrams you used to determine your answer and explain in detail each reasoning you followed to solve the problem.

Answer 1

please find the image

Mass of A = m Mass of B = M coefficients of static friction = mu_s Let F force is necessary to start sliding F.B.D of B N_f = Normal force bt Floor N_A = Normal force by A F - u_s N_A = Ma a = (F - mu_s mg /M) equation (1) F.B. D of A N_B = Normal force by B N_A = N_B (Newtons 3rd law) for sliding of A N_A = N_B = mg equation (2) ma greaterthanorequalto U_s N_B m (F - mu_s mg)/M greaterthanorequalto mu_s mg F greaterthanorequalto mu_s Mg + mu_s mg F greaterthanorequalto (M + M)