Question

A boy exerts a 36-N horizontal force as he pulls a 52-N sled across a cement sidewalk at a constant speed. What is the coefficient of kinetic friction between the sidewalk and the metal sled runners? Ignore air resistance.

Answer 1

Answer:

0.69

Explanation:

Sum of the forces on the sled in the y direction:

∑F = ma

Fn - 52 N = 0

Fn = 52 N

Sum of the forces on the sled in the x direction:

∑F = ma

36 N - Fn μ = 0

Fn μ = 36 N

μ = 36 N / Fn

Substitute:

μ = 36 N / 52 N

μ = 0.69

Answer 2

Answer:

cofficient of kinetic friction is 0.6923

Explanation:

Given Data

Coefficient of kinetic friction  μk = $f_{k}$/N where fk is force of kinetic friction and N is normal reaction;

we have N = 52 N, and fk = 36 N ;

                μk = $f_{k}$/N

                      = 36/52

                      = 0.6923

    cofficient of kinetic friction is 0.6923.