Question

The kinetic energy of an object of mass, m moving with a velocity of 5 ms−1 is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?

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Answer 1

Solution. (i) If the velocity of an object is doubled, then v = 5 × 2 = 10 m s−1. Therefore, its kinetic energy becomes 4 times its original value, because it is proportional to the square of the velocity. Hence, kinetic energy = 25 × 4 = 100 J

Answer 2

Answer:

Therefore, its kinetic energy becomes 4 times its original value, because it is proportional to the square of the velocity. Hence, kinetic energy = 25 × 4 = 100 J.