A 30 N-force toward the west is applied to an object. The object moves 50 m east during the time the force is applied. What is the change in kinetic energy of the object?
A)0.0 J
B)1.7 J
C)1.0 J
D)-1500 J
E)750 J

Question

Quizplus · Accepted Answer

The work done by the force is calculated as the product of the force and the displacement in the direction of the force. Since the force is applied westward and the object moves eastward, the displacement is opposite to the direction of the force. Therefore, the work done is negative: Work = Force x Displacement x cos(180°) = 30 N x 50 m x (-1) = -1500 J. The change in kinetic energy is equal to the work done, which is -1500 J.

A 30 N-Force Toward the West Is Applied to an Object