1. Conservation of Energy

2. Mechanical energy is the sum of potential and kinetic energies of an object.
ME = PE + KE
ME = mgh + ½ mv2
The Law of Conservation of Energy states that when friction is negligible, the total mechanical energy of a system is conserved.
Energy can be transferred or transformed but cannot be created or destroyed

3. Energy Transformation, Energy Transfer, & Systems
Change from one type of energy to another.
Energy Transfer
When a certain form of energy moves to another object.

4. Types of Systems
Open system: can exchange both energy & matter with its surroundings
Closed system: can exchange energy, but NOT matter, with its surroundings
Isolated system: CANNOT exchange energy or matter with its surroundings

5. Friction causes some of the mechanical energy to change to thermal energy
The energy is still there, just in a different form!!
Efficiency: the comparison between the amount of useful energy produced (output energy) and the original amount of energy used (input energy)

6. Lightbulb Efficiency Are lightbulbs better at producing light or heat?
Which is the best lightbulb? Use evidence from the chart.