No work is done by a force on an object if

Options

A. the force is always perpendicular to its velocity
B. the force is always perpendicualar its acceleration
C. the object has no motion but the point of application of the force moves on the object
D. the object moves in such a way that the point (of the body) of application of the force remains fixed.

Answer

A, C, D

Explanation

`dW_(F)=vecF.dvecs` if `vecF` perpendicular to `dvecs` then
`dW_(F)=0,dvecs` is displacement of point of application of force `vecv=(dvecs)/(dt)`