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प्रश्न
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.
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उत्तर
Yes.
संबंधित प्रश्न
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
A coolie does no work against the force of gravity while carrying a luggage on a road.
Give reasons for the following. No work is done if a man is pushing against a wall.
A force of 30 N acts on a body and moves it through a distance of 5 m in the direction of force. Calculate the work done by the force.
What do you understand by the term energy? Is energy a scalar or vector? How is the energy possessed by a body measured?
What is the difference between renewable and non-renewable resources?
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]
How long should an electric motor, of power 2 H.P. operate, so as to pump 5 m3 of water from a depth of 15m. [Take g = 10 N kg−1]
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.
