1. Use this diagram to answer the following questions. Assume the
balls are rolling down the hill. At position “A” the balls are not
moving. At position “B”, they are.
1. Where does the hollow, white ball have most
KE?
2. Where does the hollow, white ball have the
least KE?
3. Where does the solid, black ball have most
KE?
4. Where does the solid, black ball have least
KE?
5. Do the two balls at the top of the hill have
the same amount of KE?
6. Do the two balls at the bottom of the hill
have the same amount of KE?
A
B
Surface of the Earth
B
A
B
A
Yes, zero Joules
No

2. ReviewReview
 Energy TransferEnergy Transfer
 WorkWork
 PowerPower

3. EnergyEnergy
TransformationTransformation
Energy can beEnergy can be transformedtransformed
from one form to anotherfrom one form to another
The changing of energy fromThe changing of energy from
one form to anotherone form to another
But the total amount of energyBut the total amount of energy
never changesnever changes

4. The Law ofThe Law of
Conservation ofConservation of
EnergyEnergy
Energy can not beEnergy can not be
created or destroyedcreated or destroyed
Just ChangedJust Changed

5. The total energy before the car stops is equal to
the total energy after the car stops

6. Roller CoastersRoller Coasters
 Max GPE is at the top ofMax GPE is at the top of
the highest hillthe highest hill
 GPE changes to KEGPE changes to KE
 Max KE is where theMax KE is where the
coaster is traveling thecoaster is traveling the
fastestfastest

7. Energy
Chains
Mechanical energy
Electrical energy
Mechanical energy
Some of the mechanical
energy is transformedinto heat energydue to friction
Som
e
of the
electrical
energy is
transform
ed
into
heat energy
due
to
friction
Electrical generator
generating electricity
to make an electric
motor spin a propeller