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प्रश्न
State the amount of work done by an object when it moves in a circular path for one complete rotation. Give a reason to justify your answer.
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उत्तर
Amount of work done is equal to zero.
Work is said to be done only when there is displacement produced. In the case of a body moving in a circular path, the body comes to its original place, therefore, there is no displacement, and hence work is zero.
संबंधित प्रश्न
A force acts on a body and displaces it by a distance S in a direction at an angle θ with the direction of the force. What should be the value of θ to get the maximum positive work?
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A boy of mass 40 kg climbs up the stairs and reaches the roof at a height 8 m in 5 s. Calculate:
- the force of gravity acting on the boy,
- the work done by him against the force of gravity,
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An electric motor drives a machine which lifts a mass of 4 kg through a height of 10 m in 5 s at a constant speed. Assuming g = 10 ms-2, calculate
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Mention whether work is done or not in the following activity.
| S. No | Activity | Work done or not done |
| 1. | Pushing the door | |
| 2. | Holding a doll | |
| 3. | Sitting in a bus | |
| 4. | Pushing a wall | |
| 5. | Digging soil |
