Question

A horizontal force of 400.0 N is needed to pull a 1760 N trunk across the floor at constant speed. What is the coefficient of kinetic friction(μk)?

Answer 1

Explanation:

If it's at a constant speed then the acceleration is zero

Use the formula Fnet = ma, where Fnet is the net force on the block, m is the mass of the block and a is the acceleration.

There are two forces acting on the block: the horizontal force of 759N and the Frictional force pushing the block in the opposite direction. Therefore, Fnet = 759N - Ffriction

Therefore, 759N - Ffriction = ma = 0

Therefore, Ffriction = 759N

Fnorm opposes the gravitational force so Fnorm = mg = 100kg(9.8m/s2) = 980N

Ffriction = Fnorm * μ

Therefore, μ = Ffriction /Fnorm