Question

A 55 kg box rests on a horizontal surface. The coefficient of kinetic friction between the box and the surface is 0.30. If the box is pulled at constant velocity over the horizontal surface with horizontal applied force, what is the magnitude of the force of friction and the force applied?

Answer 1

Answer: $161.7\ N$

Explanation:

Given

Mass of the box is $m=55\ kg$

Coefficient of kinetic friction $\mu_k=0.3$

Kinetic friction comes into play when the body is moving

Here, kinetic friction opposes the applied force

kinetic friction is $\mu_kmg$

thus, the applied force is

$F=\mu_kmg\\F=0.3\times 55\times 9.8\\F=161.7\ N$