A constant force acts on a particle during three successive equal displacements. The angles between the force and the displacement are 0°, 60°, and 180°, respectively. Which statement correctly describes the nature of the work done?
The work done is positive during the first two displacements and negative during the third.
Work done by a constant force is \(W = Fd\cos\theta\).
First displacement, θ = 0°: \(W_1 = Fd\cos 0° = Fd\) (positive, maximum).
Second displacement, θ = 60°: \(W_2 = Fd\cos 60° = \frac{Fd}{2}\) (positive).
Third displacement, θ = 180°: \(W_3 = Fd\cos 180° = -Fd\) (negative).
So work is maximum in the first displacement (not the second), is not zero in the third (zero would need 90°), and differs across the three.
Hence, the answer is The work done is positive during the first two displacements and negative during the third.
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