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प्रश्न
Give one example in which a force does zero work.
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उत्तर
Work done by the earth on a satellite moving around the earth is zero, as the direction of the motion of the satellite is always perpendicular to the direction of the gravitational force.
संबंधित प्रश्न
Explain briefly why the work done by a fielder when he takes a catch in a cricket match is negative.
The S.I. unit of energy is .............
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
A body of mass 5 kg falls from a height of 10 m to 4 m. Calculate:
The loss in potential energy of the body,
A vessel containing 50 kg of water is placed at a height 15 m above the ground. Assuming the gravitational potential energy at ground to be zero, what will be the gravitational potential energy of water in the vessel? (g = 10 m s-2)
Explain degradation of energy by taking two examples of your daily life.
What is the condition for a force to do work on a body?
Fill in the blank with suitable word :
1 joule is the work done when a force of 1 __________ moves an object through a distance of one __________ in the direction of __________.
Write the formula for the work done on a body when a force acts on the body in the direction of its displacement. Give the meaning of each symbol which occurs in the formula.
Is the motion of moon around the earth in circular path an accelerated motion?
A body does 20 J of work in 10 s. What is its power?
Give an example
Chemical energy changes to heat energy.
State the amount of work done by an object when it moves in a circular path for one complete rotation. Give a reason to justify your answer.
Work done by this force at any instant is ______.
