Question

For the same kinetic energy of a body what should be the change in its velocity if its mass becomes 4 times

Answer 1

Velocity must be halved.(i.e., v becomes v/2)

Kinetic energy(K.E.) =(mv^2)/2.

Let old mass=m. Therefore new mass is 4m.

Therefore,

K.E.=(4mv^2)/2--(1)

Now if the v is changed to v/2 then the equation(1) will become K.E.=(mv^2)/2

i.e., Kinetic energy remains the same if the velocity is halved.

Hope it helps