Physics
posted by Kayla .
If a 20 kg object fell to the surgace of the Earth from a height of 30m, what would its final velocity be? (work from the energy standpoint)
I know that you said it is F * X and I'm just confused. Can you help me walk through this?

Work is defined as force * distance. The force here is weight, or mg. Work done by gravity is then mgh.
Now, that work results in kinetic energy, 1/2 mv^2
1/2 m v^2=mgh
1/2 v^2=gh
v= sqrt 2gh