Write true or false for the following statements :

When velocity is halved, its kinetic energy becomes 1/4th.

True

Explanation: Kinetic energy KE of a body of mass m moving with velocity or speed v is given by the formula:


KE = m v2


so kinetic energy is directly proportional to the mass of object and to the square of speed of the body.


KE1 = mv12


If the velocity of body is halved then kinetic energy


KE2 = mv22 where, v2 = v1


Substituting the value of v2 in the formula,


KE2 = m ( v1)2


= ( mv12)


KE2 = KE1


So kinetic energy will become 1/4 if the speed is halved.


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