1. Energy of Motion Physics of Fun (26min)

2. Energy Any change in motion requires – Energy. – Work is done when a change occurs. Work can’t be done without energy! When an object or organism does work on another object, some of its energy is transferred to that object. – Law of Conservation of Energy – Energy cannot be created nor destroyed but is transferred from one object to another.

3. Types of Energy 2 Types of Energy: 1.Potential Energy (PE) – stored energy i.Associated with position – increase an object’s height, increase the amount of PE it has. a.A roller coaster at the top of the peak b.An arrow in a bow that is drawn back c.The food you are about to eat 2.Kinetic Energy (KE) – energy of motion i.Depends on the objects mass and velocity a.Double an object’s mass = double it’s KE b.Double an object’s velocity = quadruple it’s KE a.An arrow flying b.A bus moving c.A rock rolling down a hill

4. Identifying Potential & Kinetic Energy 1.What type of energy did the ball have as the girl held it at the top of the cliff? 2.What type of energy did the ball have after she let the ball go? 3.When would kinetic energy be the greatest? Potential Energy Kinetic Energy Just prior to hitting the ground

5. Identifying Potential & Kinetic Energy 1.At what location(s) would the biker have kinetic energy? 2.What type of acceleration would the biker have at A? 3.At what location(s) would the biker have potential energy? 4.Where would the biker’s kinetic energy be the greatest? Why? A & C B C – greater velocity A B C Negative Acceleration – slowing down

6. Potential & Kinetic Energy Would Student A or Student B have the least Potential Energy? Would Student A or Student B have the greater velocity? Would Student A or Student B have the greater Kinetic Energy? Student A – lower height Student B – longer fall Student B – greater velocity = greater KE

7. Potential vs. Kinetic Kinetic Energy can NEVER be greater than Potential Energy. – Energy is lost due to friction and/or gravity. Bounce a ball, the second bounce will be shorter than the starting height of the first bounce. – Gravity pulls the ball down – Air resistance (friction) slows the ball down as it falls. – A roller coaster will never have a second height higher than the initial drop off.roller coaster Friction turns energy into heat and slows it down.

8. Potential vs. Kinetic Energy At what location does the ball have the greatest potential energy? At what location does the ball have the greatest kinetic energy? What factors affect the bounce at D and make it so it will not reach the same height as A again? A C Gravity and air resistance