Question

If an object with a mass of `12 kg` changes speed from `3 m/s` to `1m/s`, by how much does its kinetic energy change?

Answer 1

decrease by `48\ J`

Explanation:

Change in kinetic energy of an object of mass `m=12` kg due to change in speed from `v_1=3m/s` to `v_2=1m/s`

`=1/2mv_2^2-1/2mv_1^2`

`=1/2(12)3^2-1/2(12)1^2`

`=-48\ J`

The above negative value shows that the kinetic energy of object decrease by `48\ J`