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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.
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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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