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प्रश्न
उत्तर
SI unit of power = watt
CGS unit of power = erg per second
1` W = 1 J s -1 = 107 erg s -1
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संबंधित प्रश्न
An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
Work done by a boy depends on the time in which he does work.
A coolie is moving on a road with a luggage on his head. Does he perform work against the force of gravity? Give reason for your answer.
Differentiate between energy and power.
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,
- the power spent by boy. (Take g = 10 m s-2)
MULTIPLE CHOICE TYPE
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What is the condition for a force to do work on a body?
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Can work done be zero even if force acts on the body?
State the energy changes which take place when A stone dropped from the top of a cliff reaches the ground after some time.
Give an example
Chemical energy changes to heat energy.
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.
In what way does an ‘Ideal machine’ differ from a ‘Practical machine’?
What should be the characteristic of a source of energy?
