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Potential and Kinetic Energy:

Objectives:

    1.    Define potential energy.

    2.    Define kinetic energy and describe the work-energy theorem.

Key Terms:

    potential energy    kinetic energy    work-energy theorem

Resources:

 

Notes:

Kinetic and Potential Energy:

      Energy stored in an object due to its position is Potential Energy.

      Energy that a moving object has due to its motion is Kinetic Energy.


Kinetic Energy:

Is energy of motion.

Anytime matter is in motion it has kinetic energy.

            Formula:    KE = 1/2mv2 (1/2 mass x velocity squared)

            Unit:            Joule

 

The faster an object moves, the more kinetic energy it has.

The more mass an object has, the more kinetic energy it has.

According to this equation, what effects K.E. more the mass or the velocity?

Velocity

Potential Energy:

Potential energy is called the energy of position.

Energy that is dependant on height is called gravitational potential energy.

The formula for potential energy is:

                     G.P.E.=mgh

Weight (mass x gravity) determines the amount of potential energy.

Is there potential energy in the 5 forms of energy?

Yes, potential energy can be found in fossil fuels, within the foods you eat, and the batteries that you use.  

Conservation of Energy:

It is important to understand that each form of energy does not exist separately but undergoes change from one to another without a net loss in energy.  Consider this example:

As a projectile is launched into the air KE is at its maximum.  As the projectile gains altitude PE becomes greater than KE.  At the top of its arc, PE is at its maximum.  The whole cycle reverses itself on the way down.

As you can see, the loss in KE is a gain in PE.  Energy is not lost but conserved.

Law of conservation of energy.

    Energy cannot be created nor destroyed.  It can be transformed from one form to another, but the total amount of energy never changes.

 

 

Last modified: October 15, 2002