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प्रश्न
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उत्तर
K.E ,K = `1/2`mv²
If speed is doubled;
K.E , K = `1/2` m (2v)²
or K' = 4 x `1/2` mv² = 4K
Thus K.E becomes four times
Thus if initially the K.E is 5J after increasing the speed twice, its k.E will become 4 x5 = 20 J.
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संबंधित प्रश्न
Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.
A coolie does no work against the force of gravity while carrying a luggage on a road.
What are the two kinds of mechanical energy?
A woman pulls a bucket of water of total mass 5 kg from a well which is 10 s. calculate the power used by her.
List any six forms of energy and write a short note on each of them.
A bucketful of water is to be drawn from a well ______ will be done when a ______ is applied to do this because there will be a ______ of water.
(displacement, work, force)
Mention whether work is done or not in the following activity.
| S. No | Activity | Work done or not done |
| 1. | Pushing the door | |
| 2. | Holding a doll | |
| 3. | Sitting in a bus | |
| 4. | Pushing a wall | |
| 5. | Digging soil |
Work done by this force at any instant is ______.
