Question

you are pushing a crate across the floor in the x direction using a constant force of 100 n that is directed horizontal to the floor. the mass of the crate is 50 kg and the coefficient of kinetic friction between the floor and the crate is 0.35. how much work does the normal force do on the crate as you push it 5 m?

Answer 1

The normal force does zero work on the crate as it is perpendicular to the direction of displacement, regardless of the distance moved.

Step-by-step explanation:

When you are pushing a crate across the floor, it is the kinetic frictional force that works against your applied force, not the normal force.

The normal force acts perpendicular to the displacement, therefore it does no work since work is defined as the component of force along the displacement times the displacement.

Since the normal force is perpendicular to the displacement, the angle between the two vectors is 90 degrees, and cos(90) is zero, hence the work done by the normal force is zero.