1. CHAPTER 4

2. Kinetic Energy Kinetic E – energy in the form of motion
Units are joules (J)
KE = ½ m × v 2
Mass in kg
Velocity in m/s

3. Kinetic Energy
Determine the kinetic energy of a 625-kg roller coaster car that is moving with a speed of 18.3 m/s.

4. Potential Energy Potential E – stored energy due to position
Three types of potential energy:
1. Elastic potential energy
2. Chemical potential energy
3. Gravitational potential energy

5. Gravitational Potential Energy
GPE = mass x gravity x height
GPE = m × 9.8 m/s2 x h
GPE in J
Mass in kg
Height in m

6. Gravitational Potential Energy
A 0.06kg ball starts to fall from a height of 2.9m. How much gravitational potential energy does the ball have at that height?

7. Law of Conservation of Energy
Energy can be converted back and forth between the potential and kinetic
Law of conservation of E – energy cannot be created nor destroyed, only the form changes

8. Fission vs. Fusion
Nuclear fission – breaking apart of nuclei, which releases energy
Nuclear fusion – 2 H nuclei fuse together to form a He nucleus, which also releases a large amount of energy
Ex: how the sun heats the earth