Question

If an object with a mass of `3kg` changes speed from `5m/s` to `9m/s`, by how much does its kinetic energy change?

Answer 1

`Delta KE=84" "`Joules

Explanation:

Given data:
`m=3" "`kg
`v_i=5" "`m/sec
`v_f=9" "`m/sec

`DeltaKE=KE_f-KE_i`

`DeltaKE=1/2m*v_f^2-1/2m*v_i^2`

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

`DeltaKE=1/2(3)*(9^2-5^2)`

`DeltaKE=1/2(3)*(81-25)`

`DeltaKE=1/2(3)*(56)`

`Delta KE=84" "`Joules

God bless....I hope the explanation is useful.