Two Main Classes of Energy

Introduction to the Different Types Of Energy

The 2 Main Classes of Energy

Kinetic Energy

Kinetic Energy is also known as Motion Energy. It cames from the greek word κίνηση (kinesis) which means “motion”. It's the extra energy an object possess because of it's motion. Kinetic Energy can be understood from different examples which applies or demonstrate how it was transformed to or from other forms of energy.

Concept Of Kinetic Energy

The faster the body moves the more kinetic energy is produced. The greater the mass and speed of an object the more kinetic energy there will be. As the train accelerates down the hill the potential energy is converted into kinetic energy.

KE = (1/2)mv2

where:

KE = Energy (in Joules)

m = mass (in kilograms)

v = velocity (in meters/sec)

*Trivia:

According to wikipedia: The Greek word

κίνηση

kinesis that means motion in english has the same root as in the word cinema which refers to motion pictures.

“The work needed to accelerate a body of a given mass from rest to it's current velocity.”

An object exerts it's kinetic energy during acceleration and maintains it unless it's speed changes. An object's kinetic energy is completely relative.

For example, if you are looking on a moving car, the car has kinetic energy according to your reference frame, but in the car's (the one you are looking) perspective, it has zero since the reference frame is moving along with the object. The total kinetic energy of both object does not completely removable by choosing the reference frame, unless all of the objects have the same velocity being exerted to move.

*Trivia: Did you know that Einstein's Über die spezielle und die allgemeine Relativitätstheorie E=mc² is also related to kinetic energy? Kinetic Energy was defined as mc² / √1-v²/c²

Potential Energy

Potential Energy is also known as the Stored Energy of an object. An object's potential energy may be the result of it's current postion or configuration of different parts of a specific system. Any object has potential energy that can be converted to different energy forms. A formal definition for Potential Energy is that it is the difference between the energy of an object in a certain position and it's energy at a reference position.

Concept Of Potential Energy

The potential energy U is equal to the work you must do to move an object from the U=0 reference point to the position r. The reference point at which you assign the value U=0 is arbitrary, so may be chosen for convenience, like choosing the origin of a coordinate system.

The force on an object is the negative of the derivative of the potential function U. This means it is the negative of the slope of the potential energy curve. Plots of potential functions are valuable aids to visualizing the change of the force in a given region of space.

*Trivia:

The word “Potential Energy” was first coined by William Rankine, a physicist and an engineer in 19^th century Scottland.

PE = mgh

where:

PE = Energy (in Joules)

m = mass (in kilograms)

g = (9.8 m/sec2) the gravitational acceleration of the earth

h = height above earth's surface (in meters)

Potential Energy exists where there is a force which pulls a certain object back to another position where lower energy can be found. It's like stretching a rubber band from it's initial postion and then releasing it. The Principle of Conservation of Energy states that "Energy cannot be created nor destroyed; Hence, Energy cannot disappear. Instead, it is stored as potential energy. If the rubber band is released or the mass is dropped, the stored energy will be converted into kinetic energy by the restoring force, which is elasticity in the case of the rubber band, and gravity in the case of the mass.

*Trivia: Gravity as we know is another form of Potential Energy.