Question

If the velocity of a body is halved and mass is doubled what will be the
change in its kinetic energy?

Answer 1

Answer:

KE =1/2mv2

according to condition ,

v=v/2

m=2m

then KE' =1/2(2m)(v/2)2

=1/2×(2m)(v2/4

=2mv2/8

mv2/4

1/2(1/2mv2)

KE'=1/2KE

Answer 2

Answer:

The change in kinetic energy is -(mv²)/4.

Explanation:

The kinetic energy of a body of mass 'm' moving with a velocity 'v' is calculated using the equation:

K.E = (mv²) / 2

When the mass of the body is doubled and the velocity is halved, the new mass and velocity will be:

m' = 2m and v' = (v/2)²

Then the new kinetic energy can be calculated as:

K.E' = (2m × (v/2)²) / 2

      = (mv²) / 4

So the change in kinetic energy will be:

Change in K.E = K.E' - K.E

                        = (mv²) / 4 - (mv²) / 2

                        = (mv²) [ 1/4 - 1/2]

                        = (mv²) [-1/4]

                        = - (mv²) / 4