Question

If an object with a mass of `5 kg` changes speed from `5m/s` to `7m/s`, by how much does its kinetic energy change?

Answer 1

Equation: `E_(k)=1/2*m*v^2`

Explanation:

At `5m//s`: `E_k=1/2*5*5^2=62.5J`

At `7m//s`: `E_k=1/2*5*7^2=122.5J`

Difference: `122.5-62.5=60J`

Check your answer :
Kinetic energy changes as the square of the velocities:
`(7/5)^2=1.96`, allmost double. Check!