1. Potential and Kinetic Energy

2. Work and Energy Work = force x distance Work is only done when an object changes position Expressed in joules Energy = the ability to do work Energy can be present in any object at any time Can only be observed when energy is being transferred from one object/system to another Amount of energy can be measured by how much work is done Expressed in joules

3. How is all energy divided? Potential Energy Kinetic Energy All Energy Gravitation Potential Energy Elastic Potential Energy Chemical Potential Energy

4. What is Potential Energy? oEnergy that is stored and waiting to be used later

5. What is Gravitational Potential Energy? oPotential energy due to an object’s position oP.E. = mass x gravity x height gravity x height o PE = mgh

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

7. More Examples of Elastic Potential Energy

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

9. Another Example of Chemical Potential Energy

10. What is Kinetic Energy? KE = ½ mv 2 oEnergy an object has due to its motion oK.E. =.5 x mass x speed 2

11. Law of Conservation of Energy Energy cannot be created or destroyed Energy changes form It’s transferred Total energy in a system remains the same

12. Energy Systems Closed – energy being transferred in and out is minimal (can be ignored) Open – exchange energy with space around them

13. Energy Transfer oKE is transferred into PE oPE is transferred into KE

14. Notice that the “total” energy in the system stays the same Energy Transfer

16. Wylie Coyote and Roderunner Cartoons

17. You try! http://www.eduplace.com/kids/hmsc/activities/simulations/gr4/unitf.html