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Question Question 2(iv)
A force of 20 N displaces a body by a distance of 4 m. Find the amount of work done when the displacement is:
(a) in the direction of force.
(b) at an angle of 60° with the force.
Given,
Force (F) = 20 N
and
Displacement (s) = 4 m
(a) When displacement is in the direction of force, θ = 0°
W = Fs cos θ°
= Fs cos 0°
= 20 x 4 x 1 [∵ cos 0° = 1]
= 80 J
(b) When displacement is at an angle 60° with the direction of force,
W = Fs cos θ°
= Fs cos 60°
= 20 x 4 x [∵ cos 60° = ]
= 40 J