Forms of Energy

QOD

1. What are the 5 types of energy?2. Potential Energy and Kinetic Energy

are examples of what type of energy?

QOD- Answers

1. What are the 5 types of energy?1. Mechanical (moving energy)2. Chemical3. Electromagnetic4. Thermal (heat)5. Nuclear

2. Potential Energy and Kinetic Energy are examples of what type of energy?

MECHANICAL ENERGY!

Forms of Energy

Mechanical – involves movement or the potential for movement (2 forms)

1. Potential Energy – stored energy (PE)-Not moving energy, but potential to move-“Gravity” is the force acting on an object will

move if allowed to-Impacted by Mass, Gravity and “Height”

2. Kinetic Energy - Energy in motion (KE) Impacted by - Mass and Velocity

How Energy is Related to Work…

How Energy is Related to Work…

Once the bow is released, what kind of energy is found in the arrow?

Equations

Potential Energy = (mass)(gravity)(height)PE = m x g x h

Units of measurement Mass = kg Gravity = m/s2

Height = meters

Units for Potential Energy = Kgm2/s2 = Newton meter or a JOULE (J)

Kinetic Energy = (1/2)(mass)(velocity2) KE= 1/2 mv2

Units for Kinetic Energy = Newton Meters or JOULES(J)

Equation Chart…

UPDATE EQUATION CHART WITH POTENTIAL ENERGY AND KINETIC ENERGY :)

Examples of PE and KE

Roller Coasters Ski Mountains

Make mucho $ on PE & KE (you pay for PE-lift ticket) Rain Forest Zip-Lines

Water Slides Pendulums (physicsplace.com)

Examples of PE and KE

Can you think of any other real world examples of potential and kinetic energy???

Energy is Conserved

“Energy cannot be created or destroyed.”

Conservation of Energy

PE + KE = Total Mechanical Energy Energy can transfer from PE to KE

Like a see saw battle (as one gains the other loses) Ex: If total energy = 100% at all times…and there is 25% PE then there would be ___ KE

You can never gain more energy than you started with…

you can’t gain more height without added force!

Converting Energy PE --> KE

In Theory… 100% PE converts to 100% KE

So PE = KE

mgh = 1/2 mv2

Can you predict velocity based on height of an object? (hint: solve for velocity)

Velocity = square root of (2*g*h)

Think Pair Share…

Energy Analysis Examples

(add these problems to your notes)

Roller Coaster Physics

1. Name two of the forces that affect the motion of the car while it moves on the roller coaster.

2. Describe how the potential and kinetic energy of the car change as the car rolls downhill.

3. Can the car reach point X on the track? Why or why not?

Physics Place Pendulum Fig.

www.physicsplace.com Choose the top middle book (blue/green, 10th ed.) User: bergmann12 Password: mustangs1

1. Does the total amount of energy in the swinging pendulum change?

2. How are PE and KE related?3. When the PE is very high, is it possible for

the KE to be very high as well?4. When the pendulum has a KE of 82% of

the total energy, what would you assume the PE of the pendulum to be?

Pendulum Calculation

1. If h = 20 cm and the purple ball has a mass of 10 kg, then what is the PE of this pendulum?

2. What would be the pendulum’s velocity at the spot where the pendulum is at it’s lowest point?

Euler’s Disk

1. What form of energy is occurring here?

2. When the disk starts, does it have more potential energy or kinetic energy?

3. Does the disk gain energy as it falls? Support your answer with your thoughts.

Hot Wheels Ramp

1. Suppose the car is at rest at the top of the ramp. Calculate it’s PE and KE.

2. After the car is rolling down the ramp, calculate it’s PE and KE at the very instant before it is stopped at the bottom of the ramp.

Nerf Gun

1. How could you give the darts in the gun PE (2 ways)?

2. What happens to the PE once you pull the trigger of the gun?

Bowling Ball Pendulum

1. Will this demo hurt?2. Explain your response to #1

http://video.google.com/videoplay?docid=1096316663622604841&q=bowling+ball+pendulum&hl=en

Penguin RacePhysics in Action

Penguin Race Questions1. What type of energy do the penguins acquire

as they climb?2. What type of energy do the penguins acquire

as they slide down the track?3. Work transforms energy from one form to the

other. What is doing the work as the penguins slide down the track?

4. The D cell battery that powers the toy provides what type of energy?

5. The penguins can climb due to energy supplied by the dry cell battery.

What does the work in this energy transition?

Penguin Race Questions

6. Energy is conserved in a closed system. Does all of the dry cell energy go into raising the penguins? Why?

7. Is the energy the penguins “acquire” by climbing to the top of the ladder equal to the total amount of energy at the bottom of the track? Why?

8. Friction can do work. Lists all places that friction exists in this toy.

9. Are the penguins at their “terminal velocity” when sliding down the track? How do you know?