Question

If an object with a mass of `7 kg` changes speed from `3 m/s` to `8m/s`, by how much did its kinetic energy change by?

Answer 1

I found: `DeltaK=192.5J`

Explanation:

You know that kinetic energy is given as:
`K=1/2mv^2`

So the change in kinetic energy will be:

`DeltaK=1/2mv_f^2-1/2mv_i^2=`

`=1/2m(v_f^2-v_i^2)=`

`=1/2*7*(8^2-3^2)=7/2(64-9)=192.5J`