Calculating Energy: 5.8Kg Body from 2.3m/s to 1.5m/s

[pat666]

Homework Statement

How much energy could be derived from slowing a body of mass 5.8Kg from 2.3m/s to 1.5m/s?

Homework Equations

The Attempt at a Solution

I don't even know what formula to use here so if someone could give me a couple of formlula that would be good to start with. thanks

 

[Gear300]

You could find the change in kinetic energy (energy of motion). Ke = (1/2)*m*v^2

 

[pat666]

I have tried that and it doesn't work for me??