A 52N sled is pushed across a cement sidewalk at a constant speed. A horizontal force of 36N is exerted. What is the coefficient of sliding friction between the sidewalk and the metal runners of the sled?
At constant speed the net force on the sled is zero (Newton's 1st law of motion). The frictional force is given by μ*weight where μ is the coefficient of friction.
μ*52 = 36
μ = 36/52
μ ≈ 0.692