A 5 kg block rests on a 10 kg block on a frictionless floor. The coefficient of friction between them is 0.5. If the friction force between the blocks is 20 N, find the external horizontal force applied on the 5 kg block.

Question

G1 Physics · Accepted Answer

The 10 kg block is accelerated only by friction, so a = 20/10 = 2 m s⁻². For the 5 kg block, F-20 = 5×2 = 10 N. Therefore F = 30 N.