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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
How is work done by a force measured when the force is in the direction of displacement?
What are the S.I. and C.G.S units of work? How are they related? Establish the relationship.
Name the quality which is measured in kW.
What do you mean by a centrifugal force?
State two conditions for work to be done.
State the practical unit mainly used in mechanical engineering and write down its equivalent in watt.
A coolie carrying a load on his head and moving on a frictionless horizontal platform does no work. Explain the reason why.
A coolie carries a load of 30 kgf through a distance of 500 m in 5 minutes while another coolie B carries the same load through the same distance in 10 minutes. Compare the
(i) work done, and
(ii) power developed. (Take: g = 10md−2)
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
