Question

Identify the incorrect statement: 

No work is done by a force F on an object if:

विकल्प

• the object is stationary but the point of application of force moves on the object.

• the object moves in such a way that the point of application of force remains fixed.

• the force is always perpendicular to velocity.

• The force is always perpendicular to acceleration.

Answer 1

The force is always perpendicular to acceleration.

Explanation:

No work is done when displacement is zero or when force is perpendicular to displacement/velocity. But a force cannot be always perpendicular to acceleration because, by Newton’s second law, force and acceleration act in the same direction.