How Do I Use a Potential Energy Formula?

The basic potential energy formula, PE = mgh, is most commonly used in a straightforward manner. In order to calculate the potential energy of an object (PE), multiply the object's mass in kilograms (m) by the Earth's gravitational constant (g) and the height of the object from the floor in meters (h). The formula can also be manipulated to compute for the value of a missing variable; mass, for example, can be calculated by dividing the object's potential energy by the gravitational constant and its height, or g = PE/gh. Since an object's potential energy is equal to its kinetic energy in a vacuum, the potential energy formula can also be used to determine its kinetic energy. The same applications can be used for more complicated types of potential energy formulas, such as electrostatic or nuclear potential energy.

Most people use the basic iteration of the potential energy formula to determine how much work would be generated by an object if it were to fall from a fixed height. This allows individuals to determine the energy generated by an object if it were to experience the simplest form of motion, making it one of the more accurate approximations of the object's energy capabilities without the added force of a propelling action. The formula's convention of using the Earth's gravitational pull, measured at 9.8 meters per second squared (m/s²), is made on the assumption that most relevant actions would take place within the planet's gravitational field. Some scientists prefer to be clear about this distinction, referring to the commonly-used formula as the gravitational potential energy formula.

Individuals can use the potential energy formula to determine an object's potential energy from a fixed height, or to calculate the change in its potential energy should the object be transferred to another height. This is done by altering the formula from PE = mgh to PE = mg(h1-h2), in which h1 is the greater height and h2 is the lesser one. The change in potential energy can impact several considerations in assorted fields, such as engineering and mechanical design.

Manipulation of the formula can help individuals identify missing variables. If the object's height within the system is unknown, the formula can be altered to h = PE/mg, wherein the height is equal to the potential energy divided by the object's mass and the gravitational constant. Since g bears a constant value in the equation, there is often no need to solve for it, unless the object is at a location in which the pull of gravity differs.