2. Kinetic and Potential Energy

3. 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

4. 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.

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

6. 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

7. What is Elastic Potential Energy? oPotential energy due compression or expansion of an elastic object. Notice the ball compressing and expanding

8. What is Chemical Potential Energy? oPotential energy stored within the chemical bonds of an object

9. 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.

10. 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

11. Definition of Kinetic Energy… The energy of motion.

12. Examples of Kinetic Energy… Shooting a rubber band. Water falling over the fall. A Yo-Yo in motion. Releasing the arrow from the bow.

13. 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.

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

15. Check for understanding Answer the following questions!

17. The diagram above shows a barrel moving toward a waterfall. The barrel will have the greatest potential energy at which of these locations? A W B X C Y D Z

19. Which of the following best represents stored potential energy? A Air leaking from a flat tire B Stress built up in a rock fault C Heat given off by a forest fire DWater flowing through a hose

20. At which point on the roller coaster will the car have the greatest amount of potential energy? Kinetic energy? AW B X C Y DZ

21. Answers 1.C 2.A 3.A 4.B 5.A, B Remember – Earth can store energy (potential) and release energy (kinetic) in earthquakes or volcanic eruptions

22. The End...