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Question
A force F acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of force.
What should be the angle between force and displacement so that the work done is
- Zero
- Maximum
Solution
Angle between force and displacement to get
Component of displacement in the direction of force.
Component of force in direction of displacement
W = F × Component of displacement
= F · cos θ
W = F · S cos θ
W = S · F cos θ
(i) Zero work is 90°
(ii) Maximum work is 0°. ...`[(∵ cos 90° = 0),(∵ cos 0° = 1)]`
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