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Question
A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.
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Solution
- The mass of 10 kg is transported horizontally from point A to B. Gravity acts vertically downward. Thus, the mass moves at a right angle to the force of gravity. So,
- Work done on the item by the force of gravity = Fs cosθ = Fs cos90° = 0 (∵ cos 90 = 0).
- Therefore, the gravitational pull on the object does not work.
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