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Question
What happens to the work done when the dispacement of body is at right angles to the direction of force acting on it? Explain your answer.
Solution
When the force is perpendicular to the direction of motion, the work done in such cases is zero. We have a relation as,
W = FS cos θ
Where,
(W) - Work done
(F) - Force
(S) - Displacement
(θ) - Angle between force and distance
When the force is perpendicular to the direction of motion, cos 90° = 0, and hence the work done is also zero.
Example - The work done by the earth on a satellite moving in a circular orbit around it is zero because gravitational force of attraction and displacement of sattelite at any instant are perpendicular to each other.
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