For two 2 kg blocks, μₛ = 0.6 and μₖ = 0.4 both between the blocks and between the lower block and ground. A horizontal tension T is applied to the lower block. Find T when the upper block just begins to slip relative to the lower one.

Question

G1 Physics · Accepted Answer

At impending relative slip, the upper block can have at most a = μₛg = 6 m s⁻². The lower block is already sliding on the ground, so ground friction is μₖ(4g)=16 N. For the two-block system, T-16 = 4×6 = 24 N. Thus T=40 N.