1. Energy  Change Requires Energy  What is energy? –The ability to cause change or do work  Is energy scalar or vector?

2. Types of Energy  What types of energy do you know about?

3. Kinetic energy  What does kinetic mean? –Moving  What is kinetic energy (KE)? –Energy due to movement.  We can calculate KE:  Demo

4. You Do It!  A jogger with a mass of 60.0 kg is moving forward at a speed of 3.0 m/s. What is the jogger’s kinetic energy from this forward motion?  A 1500 kg car doubles its speed. By how many times does the kinetic energy from the car’s forward motion increase?

5. Potential Energy  What does potential mean?  What does potential energy mean? –Energy that is stored  There are 3 types of potential energy that we will talk about.

6. Potential Energy  The 3 types: –Elastic potential energy  Energy that is stored by compressing or stretching an object. –Chemical potential energy  Energy that is due to chemical bonds. –Gravitational potential energy (GPE)  Energy that is due to the gravitational forces between two objects.

7. Gravitational Potential Energy  We can calculate Gravitational Potential Energy: gravitational potential energy (J)= mass (kg) x gravity (m/s 2 ) x height (m) GPE= mgh

8. Calculations  A 4.0 kg ceiling fan is placed 2.5 m above the floor. What is the GPE of the Earth- ceiling fan system?  A 8.0 kg textbook is placed on a 1.25 m high desk. How large is the GPE of the textbook-Earth system relative to the floor?  From the above question: –How large is the GPE of the textbook-Earth system relative to the desk?

9. Law of Conservation of Energy  What does it mean? –Think about our other “Laws of Conservation”  What two general types of energy are being conserved? –KE –PE

10. Energy Transformation  Mechanical Transformation –The sum of the KE and PE in a system.  Includes: –KE, elastic PE, GPE  Excludes: –Nuclear energy, thermal energy, or chemical PE

11. Mechanical Transformation  Energy is NOT necessarily conserved.  Energy is ONLY changed between different types of mechanical energy.

12. Falling Objects  Does an apple on the tree have kinetic energy?  Does an apple on the ground have kinetic energy?  What about when it is falling, what kind of energy does it have?

13. Projectile Motion KE- High GPE-Low KE- Low GPE-High KE- High GPE- Low

14. Swings