In which one of the following situations is zero net work done?
A)A ball rolls down an inclined plane.
B)A physics student stretches a spring.
C)A projectile falls toward the surface of Earth.
D)A box is pulled across a rough floor at constant velocity.
E)A child pulls a toy across a rough surface causing it to accelerate.

Question

Quizplus · Accepted Answer

If a box is pulled across a rough floor at constant velocity, the net work done on the box is zero because the force of friction acting on the box is equal and opposite to the force applied to move the box. This means that the work done by the applied force is canceled out by the negative work done by the frictional force, resulting in zero net work.

In Which One of the Following Situations Is Zero Net