Gravitational potential energy = mass × gravity × height
Ep = (4)(9.81)(3)
Energy = 117.72 Joules
= 1.2x10^2 Joules
It’s C
Cause Impulse is found by multiplying the force and change in time (which is simply time)
So if you rearrange the equation for time you end up dividing Impulse by force.
The same way as the trees with green leaves. Through photosynthesis :)