As we know that gravitational potential energy is given by
![U = mgH](https://tex.z-dn.net/?f=U%20%3D%20mgH)
here we have
m = mass = 120 kg
![g = 9.81 m/s^2](https://tex.z-dn.net/?f=g%20%3D%209.81%20m%2Fs%5E2)
h = height = 8.2 m
now from above formula
![U = 120kg (9.81 m/s^2) (8.2 m)](https://tex.z-dn.net/?f=U%20%3D%20120kg%20%289.81%20m%2Fs%5E2%29%20%288.2%20m%29)
![U = 9653.04 J](https://tex.z-dn.net/?f=U%20%3D%209653.04%20J)
so above is the gravitational potential energy of the couch
The two balls separate but continue to move in the same direction
Each hour 430 quintillion Joules of energy from the sun hits the Earth.
In a year it is very hard to determine because of the night and different light levels.