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प्रश्न
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उत्तर
The work done by the gravitational force of the earth on a satellite revolving around the earth is zero because the motion of the satellite is perpendicular to the force at every point.
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संबंधित प्रश्न
State the S.I. unit of energy.
Define 1 joule of energy.
A weight lifter lifted a load of 200 kgf to a height of 2.5 m in 5 s. Calculate:
- the work done, and
- the power developed by him. Take g = 10 N kg-1
State the law of conservation of energy.
A max X goes to the top of a building by a vertical spiral staircase. Another man Y of the same mass goes to the top of the same building by a slanting ladder. Which of the two does more work against gravity and why?
A boy tries to push a truck parked on the roadside. The truck does not move at all. Another boy pushes a bicycle. The bicycle moves through a certain distance. In which case was the work done more : on the trick or on the bicycle? Give a reason to support your answer.
Each of the following statement describes a force acting. Which force is causing work to be done?
Its moment of a force scalar or a vector quantity?
A girl of mass 50 kg runs up a flight of 40 steps in 20 seconds. If each step in 20 cm high, calculate the power developed by the girl. (g= 10 ms-2).
A bullet is of mass 'm' g and is moving with a velocity 'v' m/s. Find the kinetic energy of the bullet when
(a) The mass is doubled,
(b) The velocity is tripled.
