Question

What is the kinetic energy of an object with a mass of `10 kg` that has been in freefall for `2 s`?

Answer 1

I found `K=1,920,8J`

Explanation:

There are two ways to find this:
1) evaluate the velocity and use, for the kinetic energy, `K=1/2mv^2`;
2) evaluate the potential energy `U` at the start that will be converted into kinetic energy:

From this:
`U=mgh=10*9.8*19.6=1,920.8J`
This potential energy at the top will be changed entirely into kinetic energy (neglecting friction).