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प्रश्न
State two conditions for work to be done.
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उत्तर
The two conditions are:
(i) Application of-force on the body.
(ii) Displacement of the body in the direction of the force.
संबंधित प्रश्न
When a body moves in a circular path, how much work is done by the body? Give reason.
(Hint: The body is acted upon by the centripetal force.)
A body of mass m is moving with a uniform velocity u. A force is applied on the body due to which its velocity changes from u to v. How much work is being done by the force?
What is meant by a rotatory motion? Give one example.
What do you mean by a centrifugal force?
Work is a scalar quantity because it is a measure of transfer of energy without indicating any direction
State the condition when the work done by a force is negative. Explain with the help of examples.
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.
State the condition when the work done by the force is negative.
The world record for weight lifting was held by Sergei Didyk of the USSR. He lifted 261 kg to a height of 2.3 m in 4s; find:
(a) Weight lifted by him
(b) Work done by him
(c) Power developed by him. (g = 10m/s2)
