Question

Figure shows two blocks in contact sliding down an inclined surface of inclination 30º. The friction coefficient between the block of mass 2.0 kg and the incline is μ₁, and that between the block of mass 4.0 kg and the incline is μ₂. Calculate the acceleration of the 2.0 kg block if μ₁ = 0.30 and μ₂ = 0.20, Take g = 10 m/s².

Answer 1

(a) From the free body diagram

R = 4g cos 30°

(b) In this case, the 4 kg block will move at a higher acceleration because the coefficient of friction is less than that of the 2 kg block. Therefore, the two blocks will move separately. By drawing the free body diagram of 2 kg mass, it can be shown that a = 2.4 m/s²