A force F = (3î + 4ĵ) N displaces a body by d = 5î m. How much work is done?
Correct answer B. 15 J
Explanation
W = F·d = (3)(5) + (4)(0) = 15 J. Only the component of force along the displacement does work; multiplying the force magnitude 5 N by 5 m gives the wrong 25 J.
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