What is the kinetic energy of an object with a mass of 3 kg that has been in freefall for 22 s?

E=0.5mv^2

That's the formula for kenetic energy. The only unknown we don't have is the velocity. In perticular the final velocity. To find this final velocity we need to use kinematic equations. Since we have the time and I'm also assuming that the initial velocity was zero we're going to use Vf=Vi+at. The acceleration is 9.8m/s^2 because its free fall and we have the time 22s. Vf = 9.8*22=215.6m/s

Now that we have the final velocity plug it in to the kenetic energy formula.

=0.5*3*215.6^2 = 69725.04J