Potential Energy: Definition

Potential energy includes energy that is related to configuration, position, or condition. It is energy presently stored that has the capability to perform work at a later time. While kinetic energy can be related with an object's motion, on the other hand, potential energy can be related to the position or configuration of an object relative to other objects or forces.

The formula for Potential Energy

Gravitational potential energy is probably the most common form of potential energy and basically depends directly on the height of an object above the ground.

The amount of gravitational potential energy an object can possess may be determined by the use of the following formula:

PE=mgh

Where,

PE = the potential energy of the object in Joules, J
m= mass of object in kg.
g = acceleration due to gravity in ms-2
h = Height of an object above the reference point in m.

Example Of Potential Energy

In a Roller Coaster , The car at the top of a roller coaster has maximum potential energy. As it drops, potential energy begins to change over into kinetic energy and creates a forward speed. How steep the initial drop is determines how fast the roller coaster travels during the ride.

Derivation Of Potential Energy

The potential energy function for a conservative force says that the force acting on an object can be given as,

potential energy formula

Here, the force acting on the object can be given as

F = mg and the distance from the point of reference can be given as h.

Substituting these values we get,

potential energy formula

Here, h1 represents the height of the reference point, while h2 represents the height above which the object is placed.

Solved Problems

Problem 1: A ball of mass 0.8 kg is dragged upward on the inclined plane. Find the total potential energy gained by this ball. The height of the wedge is 0.2 meter.

Solution:

It is given that the mass of the object m = 0.8 kg.

Since the potential energy of the object is only dependent on its height from the reference position, we can say that ,

PE = mgh

Where,

m = 0.2 kg

g = 10 m/s2

h = 0.2 m.

Therefore,

PE = mgh

PE = 0.8 × 10 × 0.2

PE = 1.6 J

Problem 2: An iron block-laden wagon is pushed up the inclined plane to the top. The total mass of the wagon is 50 kg, while the height from the ground of the topmost point is 5 meters. Calculate the total potential energy of the wagon at the top of the inclined plane.

Solution:

Given:

m = 50 kg

g = 10 m/s2

h = 5 m

Therefore we get,

PE=50×10×5

PE = 250 J

Energy Formula

Energy, in physics, is the measure of the ability to do work and it comes in many forms; the calculations for each type of energy can also be done using specific formulas. Here on this study guide, we will look over the most common energy formulas, starting from Kinetic Energy, Gravitational Potential Energy, Elastic Potential Energy, Mechanical Energy, and ending with Thermal Energy.The SI unit of measurement for energy is in Joules, and the dimensional formula is expressed as,

Dimensional formula of energy: M1L2T-2

That is, energy depends on the mass of an object, the square of the length-or distance-and the inverse square of the time dimension. This type of dimensional analysis is useful in the checking of consistency of equations containing energy and also in bringing forth relationships between quantities.

Other Related Sections

Frequently Asked Questions

Ptolemy’s Theorem