1. Homework Questions?

2. Unit 3: Energy and Momentum
Energy Objectives:
1. Define work and calculate the work done by a force.
2. Calculate the kinetic energy of a moving object.
3. Determine the gravitational potential energy of a system.
4. Calculate the power of a system.
5. Apply conservation of energy to analyze energy transitions and transformations in a system.
6. Analyze the relationship between work done on or by a system, and the energy gained or lost by that system.
7. Use Hooke's Law to determine the elastic force on an object.
Calculate a system's elastic potential energy.

3. Kinetic and Potential Energy

5. Kinetic Energy Kinetic energy is energy of motion. KE = Kinetic Energy
m = mass
v = velocity

12. Potential Energy
Potential Energy (PE) is energy an object has due to its position
Gravitational potential energy (PEg) is the energy an object has because of its position in a gravitational filed (height).

13. So the formula could also be re-written as
Note!
We know that
PEg = mgh
But we also know
Fg = mg
So the formula could also be re-written as
PE = Fgh

18. Energy Transformations
- Energy can be transformed from one type to another.
- You can transfer energy from one object to another by doing work.
Work-Energy Theorem
Work done on a system by an external force changes the energy of the system. If they are asking about change in total energy, they are asking about work. [Note: Work is directly transferred to Kinetic Energy.]

21. Practice (We will go over 52-55 on Thursday)