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प्रश्न
What is the work done by the gravitational force on the moon that revolves around the earth?
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उत्तर
The moon is revolving around the earth. In this process, the work done by the gravitational force is zero because the displacement of the moon is at the right angle to the gravitational force.
संबंधित प्रश्न
A stone of mass m is rotated in a circular path with a uniform speed by tying a strong string with the help of your hand. Answer the following questions
1) Is the stone moving with a uniform or variable speed?
2) Is the stone moving with a uniform acceleration? In which direction does the acceleration act?
3) What kind of force acts on the hand and state its direction?
What physical quantity does the electron volt (eV) measure? How is it related to the S.I. unit of that quality?
Differentiate between work and power.
Name the quality which is measured in kW.
Work is a scalar quantity because it is a measure of transfer of energy without indicating any direction
1 kWh = ______ J.
A pump is used to lift 600 kg of water from a depth of 75 m in 10s. Calculate:
- The work done by the pump,
- the power at which the pump works, and
- The power rating of the pump if its efficiency is 40%. (Take g = 10m s-2).
`["Hint" : "Efficiency" = "useful power"/"power input"]`
State the practical unit mainly used in mechanical engineering and write down its equivalent in watt.
A force of 1 kgf displaces a body by a distance of 10 cm
(i) in direction of force,
(ii) normal to the force
(iii) at an angle of 60° to the direction of the force.
Calculate the amount of work done in each case. (Take: g = 9.8 ms−2 )
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person walks on a levelled road.
