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प्रश्न
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person climbs a ladder.
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उत्तर
Negative work is done.
Explanation:
When a person climbs a ladder (upward), the displacement covered by the person is opposite to the direction of the force of gravity (downward), so the work done on the person by the force of gravity is negative.
संबंधित प्रश्न
State the condition when the work done by a force is positive. Explain with the help of examples.
Name the quality which is measured in kW.
State the factors on which moment of force about a point depends.
A body is provided at a point. A force of 20 N is applied at a distance of 40 cm from the pivot. Find the moment of force about the pivot.
What is the work done when the force on the object and the displacement of the object are perpendicular to each other?
A man raises a box of mass 50 kg to a height of 2 m in 20s, while another man raises the same box to the same height in 50s. Calculated:
- the work done, and
- the power developed by each man. Take g = 10 N kg-1.
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. Compare:
- the work, and
- power developed by them.
A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes.
How much work each does? Take density of water = 103 kg m-3 and g = 9.8 N kg-1.
State two conditions for work to be done.
