Question

If an object with a mass of `15 kg` changes speed from `8 m/s` to `14 m/s`, by how much does its kinetic energy change?

Answer 1

I found a change of `DeltaK=990J`.

Explanation:

Kinetic Energy `K` is given as:
`K=1/2mv^2`
Considering the initial and final stages of your phenomenon you have that the change in `K` will be:
`DeltaK=K_f-K_i=1/2mv_f^2-1/2mv_i^2=1/2m(v_f^2-v_i^2)=`
`=1/2*15*(14^2-8^2)=990J`