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प्रश्न
State the condition when the work done by the force is negative.
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उत्तर
Work done by a force is negative when the displacement is in the direction opposite to the force.
संबंधित प्रश्न
A stone of mass m is rotated in a circular path with a uniform speed by tying a strong string with the help of your hand. Answer the following questions
1) Is the stone moving with a uniform or variable speed?
2) Is the stone moving with a uniform acceleration? In which direction does the acceleration act?
3) What kind of force acts on the hand and state its direction?
Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.
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A body of mass m is moving with a uniform velocity u. A force is applied on the body due to which its velocity changes from u to v. How much work is being done by the force?
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It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B of same mass does the same in 15 s. Compare the power developed by the persons A and B.
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. Compare:
- the work, and
- power developed by them.
What happens to the power if the time for doing work is reduced from t second to t/10 second?
State the C.G.S. unit of work. How it is related to its S.I. unit?
