1. Making a Nine Square
A Nine Square is a matching game that requires matches on the edges of 9 tiles that fit into a 3 by 3 grid. The information on adjacent edges should match up. To prepare for your Nine Square , being by listing the matches below. Create 18 distinct matches. There may be twoor more entries in the Match Column for each Term/idea/equation/image.
Term/idea/equation/image
Matches
Potential Energy
Gravitational *Ep
Elastic * EEL. *EG
Kinetic Energy
Gravitational Potential Energy
Elastic Potential Energy
Law of Conservation of Energy
Zero
Maximum
Mechanical Energy
Term/idea/equation/image
Matches
Joule
Unit for Energy
* Newton-meter
‘k’
Factor in EEL formula
Spring coefficient
quadruples
EKMAX

3. Energy 60 ME = KE + PE Potential energy (PE) is the energy
Energy is an important topic with scientific, political and social implications. The energy needs of modern society are growing. In science, Energy can be studied from many perspectives: Our study of Energy begins with the basics:
Potential energy (PE) is the energy
stored by an object due its position. Gravitational potential energy (Egrav)
is the stored energy due to the
vertical position of an object within
Earth's gravitational field.
Elastic potential energy (EEL) is the stored energy due to the position of an object effected by an object that deforms (like a spring or a rubber band).
Energy definition:
the ability (or capacity) to do work.
Energy unit:
JOULES
Energy is a scalar quantity.
Mechanical energy is in two forms:
Kinetic Energy Potential Energy
the energy of motion the energy of position
ME = KE + PE
Mechanical Energy of a system is the sum of the kinetic and potential energy.
Kinetic energy (KE) is defined as the energy possessed by an object due to its motion. An object must be moving to possess kinetic energy. The amount of kinetic energy (KE) possessed by a moving object is dependent upon mass and speed. 60

4. Mechanical energy: Potential Energy
Potential energy (PE) is the energy stored by an object due position. There are several forms of potential energy.
Nuclear potential energy is the potential energy of the particles positioned inside an atomic nucleus. These particles are bound together by the strong nuclear force.
Magnetic and electrical potential energies also store energy based on the position of electric charges and magnetic fields.
Gravitational potential energy (Egrav) is the stored energy due to the vertical position of an object within Earth's gravitational field.
Formula: EGRAV = mgh
Where “m” is the object’s mass, “h” is the height and “g” is the strength of the gravitational field.
A familiar story exists about Isaac
Newton being struck on the head
by an apple.
If the apple was 2 meters above the
ground and its mass was 0.5 kg,
what was the apple’s Gravitational
potential energy?
G: m = 0.5 kg, h = 2 m, g = 9.8 m/s/s
U: EGRAV
E: EGRAV = mgh
S: EGRAV = (o.5kg) (2 m) (9.8 m/s/s)
S: The apple’s gravitational potential energy
was 9.8 joules.
The food stores Chemical potential energy (ECHEM). The position of atoms in molecules stores energy in molecular bonds. When those bonds are broken, energy is released. Batteries also store energy as Chemical potential energy (ECHEM).
Elastic potential energy (EEL). Is due
to the position of a spring or elastic band.
When it is deformed (stretched or
compressed), energy is stored.
Formula: EEL = ½ k x2
Where “k” is the stiffness of the spring
and
“x” is the change
in the spring or elastic band’s length.
When mass changes by a factor, EGRAV changes by the same factor.
See page 11 to review using formulas for predictions
When height changes by a factor, EGRAV changes by the same factor. 61

5. Mechanical energy: Kinetic Energy
Kinetic energy (KE) is defined as the energy possessed by an object due to its motion. Temperature is due to the kinetic energy of the molecules in a substance. When temperature increases, the molecules move faster. Similarly, a decrease in temperature will mean the molecules move more slowly relative to each other. So, temperature is one measure of kinetic energy.
An object must be moving to possess kinetic energy. The amount of kinetic energy (KE) possessed by a moving object is dependent upon mass and speed.
Formula: EK= ½ m v2
Where “m” is the mass of the object and
“v” is the object’s velocity.
Examples:
Determine the Kinetic energy of
a 60. kg man moving at 3.0 m/s.
G: m =60. kg, v = 3.0 m/s
U: EK
E: EK= ½ m v2
S: EK = ½ (60. kg) (3.0 m/s)2
S: The man’s kinetic energy is 270 joules.
a kg bullet moving at m/s.
G: m = kg, v = m/s
S: EK = ½ ( kg) ( m/s)2
S: The bullet’s kinetic energy is joules.
When mass changes by a factor, EK changes by the same factor.
See page 11 to review using formulas for predictions
When velocity changes by a factor, EK changes by the factor squared. 62

6. The Law of Conservation of Energy
The Law of Conservation of Energy states that energy cannot be created or destroyed;
it simply changes form.
The Law of Conservation of Energy is helpful in analyzing the flow of energy in many systems.
In the food chain, energy is dissipated as each organism provides nourishment for the next one on the chain. The energy is not lost. It is converted to tissue, heat or waste.
In mechanical systems, energy is transformed to accomplish a task. When mechanical systems ‘waste’ energy, the energy that is ‘lost’ is not really lost at all. The ‘wasted’ energy which may be due to friction, vibration or sound is considered EDISS since it is energy that does not contribute to the task the mechanical system is intended to perform.
Consider the closed system at the left. In a closed system, energy does not flow in or out.
If the clay had 40 J of EGRAV before it was dropped, there would be 40 J of energy later but not all of it would be EGRAV. It could be EK (when it is moving), EEL (when it compresses the spring) or a combination.
BIOLOGY
Consider the closed system at the right.
Remember  In a closed system, energy does
not flow in or out.
If the clay had 40 J of EGRAV before it was
dropped, there would be 40 J of energy
after it hit the ground.
However, the kinds of energy in the system at the end are kinds that cannot be easily recovered: sound and heat. When energy changes to a type of energy that we cannot recover or use, this is called Dissipated energy (EDISS). Dissipated Energy is not ‘gone’; it has changed to a form we cannot recover and use. 63

7. Energy Transformations & The Law of Conservation of Energy
The Law of Conservation of Energy states that energy cannot be created or destroyed; it simply changes form. For the example below, the coaster is frictionless so no energy will be dissipated due to friction. The roller coaster below shows how the gravitational potential energy of the car at A is converted to kinetic energy as the car reaches B. When the car rolls downhill from A to B (EGRAV decreases), it speeds up (EK increases). As the coaster rolls uphill from B to C, the coaster slows down (EK decreases) as it moves upward (EGRAV increases).
At A:
Car stopped at the highest point
EGRAV = 25,000 Joules EK = 0 Joules
hA = 50. m
Car stopped at the highest point
EGRAV = 2500 Joules EK = 0 Joules
At C:
Car slowing down as it moves up hill
EGRAV = 20,000 Joules EK = 5,000 Joules A C
Finding the velocity at B:
G: EK at B = EGRAV at A
EK at B = 25,000 Joules
mcoaster = 50 kg
U: VB (velocity at B)
E: EK = ½ m v2
S: 25,000 J = ½ (50kg) v2
25,000 J = (25kg) v2
1,000 J/kg = v2
v = 32 m/s
S: The coaster is moving at
32 m/s at point B.
At B:
Car moving
at the lowest point
EGRAV = 0 Joules
EK = 25,000 Joules
hC= 40. m
mcoaster = 50. kg
g = 10 m/s/s
hB = 0.0 m B
h =
0 m
h = 0 m 64
h = 0 m

8. How WORK affects Energy
When work changes EK
By doing work stop a moving object, the kinetic energy of the object is reduced.
The brakes do work on the
car to slow it down.
The force from the
brakes that slows
the car is called a
non-conservative force since the energy is transferred to a form that cannot be recovered.
The energy is not ‘lost’. The original kinetic energy is transformed to dissipated energy(EDISS)
Energy: the ability (or capacity) to do work.
Work: the transfer of energy
Net
Force
Based on the definitions, it is clear that Work and Energy are closely related. The best way to understand this relationship is through examples.
When work changes EGRAV
By doing work against gravity to lift an object,
more energy is stored in it.
The weight lifter does work against gravity
on the dumbbell that she has raised to
shoulder height. She has stored energy
in the dumbbell by increasing its height.
Since the force to raise the dumbbell transferred to become energy stored due to its higher position, the lifting force is called a conservative force.
Work Energy Principle: WNC = (ΔKE)+(ΔPE)
so WNC = EDISS
If an object falls, it’s EGRAV is transformed to EK as it falls. If the air resistance is negligible, then as EGRAV decreases EK will increase by the same amount. In this case, the object’s weight (Fg) is the force that makes the object fall. In this case, Fg is a conservative force since all energy is converted to EK.
Putting it together:
BUT. If there is air resistance, not all of the EGRAV will change to EK. In that case, the force from air resistance will be a non-conservative force that will convert some energy to EDISS. 65