Potential energy is the energy that an object possesses by virtue of
its location. If gravity is the only force present then the potential energy
is given by the formula:
potential energy = m g h
where m is the mass of the object, g is the acceleration due to gravity (the gravitational constant), namely 9.81 m/s2, and h is the height of the object. If the object is raised then the object gains this much potential energy; if the object is lowered then it loses this much potential energy.
In the SI (metric) system of units:
• m is expressed in kg (kilograms),
• g is expressed in m/s2 (meters per second squared),
• h is expressed in m (meters),
• the energy is expressed in J (joules).
Potential energy (in fact any type of energy) can be converted into other forms of energy. For example if an object is dropped then it speeds up (gains kinetic energy) as at falls (loses potential energy).