Question

When a force retards the motion of a body, the work done by the force during retardation is

• A. Zero
• B. Negative
• C. Positive
• D. Positive or negative depending upon the magnitude of force

Answer 1

Answer: (B)

The correct option is B Negative
The work done by the force during retardation is negative. Work done(W) = F.s Cos$\theta$ where $\theta$ is the displacement angle. In this case the angle is 180 degree's (since during retardation the angle is 180 degree's).

And Cos180 is -1 ( i.e it is negative). Thus thus the work done by the force during retardation is negative.