A force of 20 N acts at 60° to the horizontal and moves a body 13 m along the horizontal. How much work does it do?
Answer and explanation
Correct answer: A. 130 J
- Step 1: Work = Fs cos θ, and cos 60° = 0.5. Step 2. W = 20 × 13 × 0.5 = 130 J. Answer: 130 J. Why not the others: 260 J is what you get if you ignore the angle. 225.16 J is what you get if you use sin 60° instead of cos 60°. 520 J is what you get if you double the work.
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