Question

A 41kg box is being pushed a distance of 7.0m across the floor by a force P whose magnitude is 158N. The force P is parallel to the displacement of the box. The coefficient of Kinetic friction is 0.25. Determine the work done on the box by each of the four forces that act on the box. The applied force, fictional force, normal force and gravity .Be sure to include the proper plus or minus sign for the work done by each force.


Work done = distance*forceP

Four forces: P, friction, gravity, normal force from floor upward.
On the normal force...notice the displacement in that direction is zero.