Question

A bucket full of water is drawn up by a person. In this case the work done by the gravitational force is:

• A. negative because the force and displacement are in opposite directions.
• B. positive because the force and displacement are in the same direction.
• C. negative because the force and displacement are in the same direction.
• D. positive because the force and displacement are in opposite directions.

Answer 1

The correct option is A negative because the force and displacement are in opposite directions.

As the gravitational force acts downward and the displacement of the bucket is upward, force acts opposite to the displacement of the body. The work done being a dot product of force and displacement vectors, becomes negative as cosine of ${180}^0$ is $-1$.