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Question
A body, when acted upon by a force of 20 kgf, gets displaced by 1 m. Calculate the work done by the force, when the displacement is
- in the direction of force,
- at an angle of 60° with the force, and
- normal to the force. (g = 10 N kg-1)
Solution
F = 20 kgf = 20 × 10 N = 200 N
Displacement S = 1 m
Work done
- When displacement is in the direction of force
W = F × S
W = 200 × 1 = 200 J - When displacement is at an angle of 60°
W = F.S cos 60°
= 200 × 1 × `1/2`
= 100 J - When displacement is normal to the direction of force
W = F.S cos 90°
= 200 × 1 × 0
= 0 (Zero)
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