Question

What is the kinetic energy of an object with a mass of `16 kg` that has been in freefall for `4 s`?

Answer 1

The kinetic ebergy will be `E_k=1/2mv^2` with `m=16kg`

Explanation:

Now the speed `v`:
Acceleration of gravity `g=9.81m//s^2`
Which means that after `t=4s` the velocity will be:
`v=gxxt=9.81xx4=39.24m//s`

Using this in the original formula we get:

`E_k=1/2xx16xx(39.24)^2=12318J~~12.3kJ`