Which one has greater potential energy? An 8 kg rock sitting on a 2.2 m cliff or a 6 kg rock sitting on a 3.2 m cliff.

The 6 kg rock sitting on a 3.2 m cliff.

Explanation:

The potential energy of an object of mass M that is at a height H above the ground us:

U = M*H*g

where g is the gravitational acceleration:

g = 9.8m/s^2

Then:

"An 8 kg rock sitting on a 2.2 m cliff"

M = 8kg

H = 2.2m

U = 8kg*2.2m*9.8 m/s^2 = 172.48 J

"a 6 kg rock sitting on a 3.2 m cliff"

M = 6kg

H = 3.2m

U = 6kg*3.2m*9.8m/s^2 = 188.16 J

You can see that the 6kg rock on a 3.2m cliff has a larger potential energy.