Energy is the ability to do work or cause change. It exists in various forms including kinetic energy, which is the energy of moving objects, and potential energy, which is stored energy. Kinetic energy is calculated as one-half mass times velocity squared, while gravitational potential energy is calculated as mass times height times gravity. Energy cannot be created or destroyed, only changed from one form to another. For example, as a roller coaster rises, its potential energy increases and kinetic energy decreases, then vice versa as it descends. The total energy remains the same as it is transferred between kinetic and potential forms throughout the ride.

1. ENERGY What is energy?

2. Energy Energy is the ability to do work to cause change Energy is required for motion

3. Kinetic energy Kinetic energy is the energy of matter in motion Types of kinetic energy Chemical Nuclear Electromagnetic Thermal Mechanical

4. Kinetic Energy Kinetic Energy (KE) = ½ mass x velocity 2 KE = 1/2mv 2 Unit = JOULE (J) = 1kg/m 2 /s 2

5. Energy Energy cannot be created or destroyed only changed or transformed Hand to Ball to Hand Chemical to mechanical to heat to mechanical to chemical

6. Potential energy Potential energy is stored energy An object at rest has the potential to have motion Kinetic – energy of motion Potential – stored energy

7. Gravitational Potential Energy GPE is the energy an object can change to kinetic if it falls GPE = mass x height x gravity (9.8m/s 2 ) KE = ½ mv 2 KE = ½(70kg) x (10m/s 2 ) 2 = 3,500 J

8. Energy Greatest potential energy – start of slide Least potential energy – end of slide Greatest kinetic energy – middle of slide Least kinetic energy – start & end of slide Total energy remains the same it is just transferred between Kinetic and Potential

9. Forces on a roller coaster http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/energy/ce.html http://science.howstuffworks.com/roller-coaster3.htm

10. Roller coaster forces

11. Energy Problems ½ (6) x 10 2 = 300 J (3 x 100) 30 x 9.8 x 15 = 4410 J 1 x 9.8 x 2 = 19.6 J ½ (1) x (2.2) 2 = 2.42 J (.5 x 4.84) ½ (1,000) x 20 2 = 200,000 J (500x400) ½ (1,000) x 40 2 = 800,000 J (500x1,600)

12. What kind of energy? An infrared lamp in a restaurant keeps food warm? Thermal A student listens to a CD player Electromagnetic and mechanical A teacher talks loudly to a classroom to get their attention Mechanical Hamburger that has been eaten at lunch Chemical