Question

If an object with a mass of `5 kg` changes speed from `3m/s` to `14m/s`, by how much does its kinetic energy change?

Answer 1

THe change in kinetic energy is `=467.5J`

Explanation:

The kinetic energy is

`KE=1/2mv^2`

The change in kinetic energy is

`DeltaKE=1/2mv_2^2-1/2mv_1^2=1/2m(v_2^2-v_1^2)`

The mass is `m=5kg`

The initial velocity is `v_1=3ms^-1`

The final velocity is `v_2=14ms^-1`

Therefore,

`Delta KE=1/2xx5xx(14^2-3^2)=467.5J`