Question

Please help A 10 kg box initially at rest is pulled with a 50 N horizontal force for 4 m across a level surface. The force of friction acting on the box is a constant 20 N. How much work is done by the gravitational force?

A. 100 J
B. 0 J
C. 10 J
D. 50 J

Answer 1

The box is being pulled horizontally, so any work done on the box must be done by forces that are parallel to the ground. But gravity always points downward, which is perpendicular to the surface in this case, so the gravitational force performs B. 0 J of work.