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प्रश्न
State the law of conservation of energy.
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उत्तर
According to the law of conservation of energy, energy can neither be created nor can it be destroyed. It only changes from one form to another.
संबंधित प्रश्न
Work done = Force × ........................................
No work is done by a force if the body
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(i) work done by machine,
(ii) power at which the machine works.
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A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
