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प्रश्न
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
उत्तर
- When a boy with mass m climbs a staircase with a vertical height of h, he works against gravity by using his own weight, F = mg and W = F x h.
- Because displacement occurs in the direction of force, W = mgh in both scenarios.
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संबंधित प्रश्न
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Give one example each in which a force does (a) positive work (b) negative work, and (c) zero work.
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(ii) K.E. maximum,
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(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
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