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प्रश्न
In which of the following cases is work being done:
- A boy pushing a heavy rock
- A boy climbing up the stairs
- A coolie standing with a box on his head
- A girl moving on the road.
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उत्तर
work being done in the following cases
(b) A boy climbing up the stairs
(d) A girl moving on the road.
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संबंधित प्रश्न
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.
Name five appliances or machines which use an electric motor.
What is meant by a translational motion? Give one example.
What is the ratio of SI units to CGS units of 'work'?
Write an expression for the work done against gravity.
Name the physical quantity whose MKS units are kgm2s-3.
A coolie, with a load of 30 kg on his head, walks on the platform. If he walks a distance of 60 m, what is the work done by him?
In the following case write yes, if the work is being done and no if no work is being done.
A boy climbing up a staircase.
A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Suma is swimming in a pond.
