A very light cart holding a 300-N box is moved at constant velocity across a 15-m level surface.What is the net work done in the process?
A)zero
B)1/20 J
C)20 J
D)2 000 J

Question

Quizplus · Accepted Answer

The net work done on an object is given by the formula: 
Net Work = Force x Distance x cos(theta) 
where theta is the angle between the force and the displacement.

In this case, since the cart is moving at a constant velocity, its acceleration is zero and therefore the net force acting on the box is also zero. Hence, the net work done on the box is zero.

A Very Light Cart Holding a 300-N Box Is Moved