1. Gravitational Potential Energy
Gravitational energy is due to the force of gravity caused by the attraction of all other masses to the mass of the earth.
As you lift an object to a higher elevation, you give that object increased gravitational energy. You can get that energy back (or most of it) when you drop the object and it falls to the earth's surface.

2. The amount of gravitational energy that an object possesses can be calculated from the equation:
GPE = m x g x h
where
GPE = gravitational potential energy
m = mass
g = acceleration of gravity
h = height above the ground (or a reference level

3. The acceleration of gravity near the surface of the earth is constant, around 9.8 m/s2
GPE is measured in Joules (J) or Kilo-joules (kJ).
1 KJ = 1000 Joules
Therefore; an object which has 1500J = 1.5kJ

4. Questions
1. How much GPE does a 82kg person standing 5m above the ground have?
2. The above person stands on a 152m mountain and then descends 68m, how much GPE have they lost?
3. A 350 gram object sits 277cm above the ground. What is its GPE?
4. A 550 gram object sits on a desk 1.2m above the ground. What is its GPE?