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प्रश्न
In which of the following cases is work being done:
- A boy pushing a heavy rock
- A boy climbing up the stairs
- A coolie standing with a box on his head
- A girl moving on the road.
उत्तर
work being done in the following cases
(b) A boy climbing up the stairs
(d) A girl moving on the road.
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संबंधित प्रश्न
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A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
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(ii) How much energy would be required in lifting the drum into the truck without the plank?
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