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प्रश्न
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
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उत्तर
- While carrying a load, the donkey has to apply a force in the upward direction. But the displacement of the load is in the forward direction.
- Since displacement is perpendicular to force, the work done is zero.
संबंधित प्रश्न
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(i) A man pushing a wall.
(ii) a coolie standing with a load of 12 kgf on his head.
(iii) A boy climbing up a staircase.
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
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Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
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A coolie, with a load of 30 kg on his head, walks on the platform. If he walks a distance of 60 m, what is the work done by him?
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