A force of 10,00 N is applied to a stationary wall. How much work is performed?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

The amount of work performed is zero.

Work is a physical quantity that is measured as a scalar, or dot product, of a force acting on an object and the displacement of the object during the time of the application of the force:

`W = vecF*vecd = F*d*cos(theta)` , where `theta` is the angle between the force and displacement.

Thus, the magnitude of work performed by a force depends on three things: the magnitude of the force, the magnitude of the displacement, and the angle between the force vector and the displacement vector.

If the force is zero, the work performed by the force will obviously also be zero. However, even if force is non-zero, the work still might be zero. For example, if the object did not change its position during the time the force acted on it, then the displacement vector is zero, and the work performed by the force is also zero. This is the case in this problem, since the wall remains stationary - there is no displacement, and the work is zero.

Also, if the angle between the force and displacement is 90 degrees - that is, the force vector and the displacement vector are perpendicular - then the work performed by this force is also zero, because cos(90) = 0. For example, in uniform circular motion, the work performed by centripetal force is zero because it is always perpendicular (normal) to the trajectory.

See eNotes Ad-Free

Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Get 48 Hours Free Access
Approved by eNotes Editorial Team