Question

A car is moving along a straight level road with constant speed. Then

• A. the work done on the car is infinite.
• B. the work done on the car is zero.
• C. the work done on the car is a measure of the gravitational potential energy.
• D. the work done on the car cannot be found.

Answer 1

The correct option is B

the work done on the car is zero.

1. According to the work-energy theorem, the work done on a body by an external force is equal to the change in its kinetic energy.
2. When a car is moving at a constant speed, there is no change in its kinetic energy.
3. Also, the car is moving on a straight-level road, so there is no external frictional force.
4. Hence, the work done on the car is zero as the change in kinetic energy is zero and there is no external force acting on it.

Thus, work done on a car moving along a straight level road with constant speed is zero.

Hence, option (B) is correct.