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प्रश्न
In which of the following cases, is work being done?
(i) A man pushing a wall.
(ii) a coolie standing with a load of 12 kgf on his head.
(iii) A boy climbing up a staircase.
उत्तर
Work is done only in case of a boy climbing up a stair case.
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संबंधित प्रश्न
Define 1 J of work.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A sailboat is moving due to wind energy.
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What are the units of (a) work, and (b) energy?
Give one example each in which a force does (a) positive work (b) negative work, and (c) zero work.
How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.
The velocity of a car increases from 54 km/hr to 72 km/hr. How much is the work done if the mass of the car is 1500 kg?
What do you mean by a kilo joule?
What is the ratio of SI units to CGS units of 'work'?
Name the physical quantity whose MKS units are kgm2s-3.
Name the physical quantity associated with the 'rate of doing work'.
A block of mass 20 kg is pulled up a slope (fig.12) with a constant speed by applying a force of 500 N parallel to the slope. A and B are initial and final positions of the block.
(a) Calculate the work done by the force in moving the block from A and B.
(b) Calculate the potential energy gained by the block.
List any six forms of energy and write a short note on each of them.
Fill in the boxe to show the corresponding energy transformation.
Write the two main conditions are needed for work to be done?
Work done by this force at any instant is ______.
