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प्रश्न
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संबंधित प्रश्न
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
When does a force perform work?
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
Can every force produce work?
Complete the following sentences:
Joule is the unit of .......
A boy of mass m climbs up a staircase of vertical height h.
- What is the work done by the boy against the force of gravity?
- What would have been the work done if he uses a lift in climbing the same vertical height?
Give an example
Electrical energy changes of sound energy.
A block of mass 30 kg is pulled up a slope, as shown in diagram with a constant speed, by applying a force of 200 N parallel to slope.
A and B are initial and final positions of block.

(i) Calculate the work done by force in moving the block from A to B.
(ii) Calculate P.E. gained by block. [g=10ms-2]
