A mason drags a bag of cement across a horizontal floor by pulling on a rope that…

PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Work Energy and Power · Work Energy and Power

Problem

A mason drags a bag of cement across a horizontal floor by pulling on a rope that makes an unknown angle θ\theta with the direction of motion. (i) The bag is pulled a distance of 8 m8\,\text{m} by a constant force of 40 N40\,\text{N}, and the work done by this force is 250 J250\,\text{J}. Calculate the angle θ\theta between the rope and the direction of motion. (ii) The mason now holds the rope so that the angle becomes 120∘120^{\circ} while keeping the magnitude of the force and the displacement the same. Calculate the work done in this case and state whether it is positive, negative, or zero, giving a brief reason.

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