Posted by Brandon on .
A 54 kg box is being pushed a distance of 7.0 m across the floor by a force P whose magnitude is 153 N. 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. Be sure to include the proper plus or minus sign for the work done by each force.
applied force:
frictional force:
normal force:
gravity:

Physics 
Damon,
mg does 0 work because there is no motion up or down
the force up on the box, also mg, does no work because there is no motion up or down.
the 153 N does positive work = 153*7 Joules
the friction does negative work = m g*.25*7