Kinetic and Potential Energy

Objectives• You will be able to define and identify Kinetic and Potential energy.

• You will be able to illustrate examples of potential and kinetic energy in everyday life (objects at rest, falling water, and geological faults) TEKs 7-8A

Definition of Energy…The ability or capacity to do work.

Measured by the capability of doing work: potential energy

or the conversion of this capability to motion:

kinetic energy.

Potential Energy…Energy due to position or stored energy.To increase the energy of an object, you can raise it to a higher elevation.

Examples of Potential Energy:Stretching a rubber band.. -Stores energy

Water at the top of a waterfall.. -Stores energy

Yo–Yo in held in your hand.. -Stores energy because of position

Drawing a Bow… -Stores energy because of position

What is Elastic Potential Energy?Potential energy due compression or expansion of an elastic object.

Notice the ball compressingand expanding

What is Chemical Potential Energy?

• Potential energy stored within the chemical bonds of an object

• When the position of an object is altered, it creates Potential Energy.

• A yo-yo on the table has limited energy but when picked up, it alters its position and now it has the ability (or potential) to do more work.

• A bow doesn’t have the capacity to do work, unless it’s held at an elevated position.

Potential Energy Converted to Kinetic Energy…

When stored energy begins to move, the object now transfers from potential energy into kinetic energy.

Standing still Running

Definition of Kinetic Energy…

The energy of motion.

Examples of Kinetic Energy…

•Shooting a rubber band.•Water falling over the fall.•A Yo-Yo in motion.•Releasing the arrow from the bow.

Summary of What You’ve Learned..Example using a coin:

• Holding a coin in you hand alters the coins original position.

• The coin has potential energy because it has ability to do work.

• Dropping the coin in the bank, changes the stored energy into motion.

• This transfers the coin’s energy from potential to kinetic energy.

Energy Stored in Earth

The Earth stores energy along fault lines which build ups (potential) and can be released as an earthquake (kinetic).

Check for understandingAnswer the following questions!

The diagram above shows a barrel moving toward a waterfall. The barrel will have the greatest potential energy at which of these locations?

A WB XC YD Z

Which of the following best represents stored potential energy?

A Air leaking from a flat tireB Stress built up in a rock faultC Heat given off by a forest fireD Water flowing through a hose

At which point on the roller coaster will the car have the greatest amount of potential energy?

A WB XC YD Z

Since you are now done……

1.Make Sure you filled in ALL your notes, go back if you haven’t.

2.Click on the link below in order to continue learning!http://phet.colorado.edu/en/simulation/energy-skate-park-basics Click ‘Run Now’ to download.