How do you calculate gravitational potential energy?

Gravitational potential energy is calculated using the formula: GPE = mgh, where m is mass, g is gravitational field strength, and h is height.

Gravitational potential energy (GPE) is the energy an object possesses due to its position in a gravitational field. To calculate it, you need to know three key variables: the mass of the object (m), the gravitational field strength (g), and the height (h) of the object above a reference point, usually the ground. The formula GPE = mgh combines these variables to give you the gravitational potential energy in joules (J).

The mass (m) is measured in kilograms (kg) and represents how much matter is in the object. The gravitational field strength (g) is typically 9.8 metres per second squared (m/s²) on the surface of the Earth, but this value can change if you are on a different planet or at a significant altitude. The height (h) is measured in metres (m) and indicates how far the object is above the reference point.

For example, if you have a 2 kg book on a shelf 3 metres high, you can calculate its gravitational potential energy by plugging the values into the formula: GPE = 2 kg * 9.8 m/s² * 3 m. This gives you a GPE of 58.8 joules.

Understanding GPE is important because it helps explain how energy is stored and transferred in systems involving gravity. For instance, when an object falls, its GPE decreases while its kinetic energy increases, keeping the total energy conserved. This concept is fundamental in physics and helps us analyse various real-world scenarios, from roller coasters to the orbits of planets.