A force of 20 N acts at 60° to the horizontal and moves a body 10 m along the horizontal. How much work does it do?
Answer and explanation
Correct answer: A. 100 J
- Step 1: Work = Fs cos θ, and cos 60° = 0.5. Step 2. W = 20 × 10 × 0.5 = 100 J. Answer: 100 J. Why not the others: 200 J is what you get if you ignore the angle. 173.2 J is what you get if you use sin 60° instead of cos 60°. 400 J is what you get if you double the work.
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