Physics

Problem

A tractor pulls a trailer through a horizontal distance of

10\,\text{m}

with a tow-cable that maintains a constant tension of

100\,\text{N}

30^{\circ}

above the horizontal. Find the work done by the tension in the cable. a)

5.0\times10^{2}\,\text{J}

8.7\times10^{2}\,\text{J}

1.0\times10^{3}\,\text{J}

-8.7\times10^{2}\,\text{J}

Intuitive explanation

Work measures how much a force actually contributes to motion in its direction. Since the cable pulls at an angle, only the horizontal component of the tension does work—the vertical part just lifts slightly but doesn't move the trailer forward. Use $W = F \cos\theta \cdot d$ , where $\theta$ is the angle between force and displacement, to capture this idea cleanly.

Intuitive explanation

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