Question Detail
Question
Under what condition is the work done by a force zero, even when the object on which it acts is displaced?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Work is given by W = F d cos θ, where θ is the angle between the force and displacement vectors. If the force is perpendicular to the displacement, θ = 90° and cos 90° = 0, so the work done is zero. An example is the normal force doing no work on an object moving horizontally.
Hint
Consider the role of the angle between the force and the direction of motion in the work formula.