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प्रश्न
Is power a scalar or a vector quantity?
उत्तर
Power is a scalar quantity.
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संबंधित प्रश्न
Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
A weight lifter lifted a load of 200 kgf to a height of 2.5 m in 5 s. Calculate:
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- the power developed by him. Take g = 10 N kg-1
A machine raises a load of 750 N through a height of 16 m in 5 s. calculate:
- energy spent by machine,
- power at which the machine works.
In which of the following case the work done by a force will be maximum : when the angle between the direction of force and direction of motion is 0° or 90°?
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?
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Choose one or more correct alternatives.
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- concentrated
- transformed from one type to another
- destroyed
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No work is done by a man moving on a horizontal road while carrying a box on his head. Explain.
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Give an example
Electrical energy changes of sound energy.
In what way does an ‘Ideal machine’ differ from a ‘Practical machine’?
A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
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(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.
A ______ should act on an object.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A donkey is carrying a load on its back.
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