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When a body moves in circular direction
The direction of force is towards the radius
And direction of displacement is along the tangent
Since tangent is always perpendicular to radius
Hence, direction of force and displacement is always 90 degree
So, Work Done is 0
Explanation
Work = Force × Distance × cos θ
Work = Force × Distance × cos 90
Since cos 90 degree = 0
Work = Force × Distance × 0
Work = 0
Hence, we can say that work done by object in moving cirular direction is 0
Example
Work done by earth in revolving around sun is 0
Work done by satellite moving around earth is always 0
Is motion of earth around sun postive, negative or zero work?
Earth revolves around sun in an almost circular orbit
Force experienced is gravitational force, which is towards the center along the radius
And displacement is along the tangent.
Since tangent is always perpendicular to the radius
Therefore, angle between force and the displacement is 90 degrees.
Hence, no work is done
Questions
NCERT Question 11 - What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.
