1. Energy Chains Can you think of how the energy flows through a car?
What would you start with?
What types of energy transformations are happening?

2. Energy Transfer and Transformation
Thermal Energy
Thermal
Mechanical
Electrical
Chemical
Kinetic Energy

4. Can you construct an Energy Chain for a person hitting a softball to the outfield?

5. Hitting a softball into the outfield
Chemical E to pick up bat from food.
Ball has PE in the air
Ball throw in air transform from PE to KE
Bat hits ball transfers KE to ball
Ball increases KE
Gravity pulls on ball
Air resistance slows ball down
8. Ball hits ground (Friction)
9. Balls KE is transferred to dirt as it flies up.

7. Constructing Energy Diagrams

8. Predict what this car is doing?
Using Font Size
Predict what this car is doing?
Coming to a stop!
The KE is deceasing over time as it is being transformed in heat and PE energy.

9. A car stopping as a standard Bar GraphKE HE

10. Using Circle Graphs
Circle graphs can be used to illustrate energy flow. Each form is a represented by a portion of the circle. Multiple circle graphs can illustrate how the amount of energy in each form changes over time.

11. What do you notice at interval 4?
Circle Graph
Examine what is happening in these circle graphs?
What do you notice at interval 4?

12. ENERGY CHAINS
Let’s look at some systems where energy transformation is taking place…(i.e. changing from one type of energy to another type of energy.)
Ramps
Cars
Bungee jumper
A Pendulum
A Hydroelectric Power Plant

13. Energy Ramp
Label sections A-E w/ the appropriate level of PE and KE
(Assume NO friction)
PE= Max A
PE= High
KE=Min B
PE= Med
KE= Low C
Use the following terms
Maximum
High
Medium
Low
Minimum
PE= Low
KE= Med D
PE= Min
KE= High E
KE= Max

14. PENDULUM E A B D C At which point is the KE greatest?
What is the velocity at that point?
Point C
5.6 m/s

15. Pendulum Energy Transformation Draw this pendulum diagram on white board
A. PE=KE?
Points 2 and 4
B. PE greatest?
Points 1 and 5
C. KE greatest?
Point 3 only
D. KE lowest?
1 and 5
E. PE lowest?
3 only

16. 1. Statement: The farther above the ground an object, such as a book, is raised, the greater the object’s Gravitational Potential Energy (GPE).
Circle the statement below which most closely matches your thinking and then explain your thinking.
1.Yes, everything has some potential energy.
2. Yes, but it only gets potential energy when it falls.
Yes, because gravity is stronger the higher you go up.
3. Yes, one thing that determines the GPE is the distance between the object and the ground.
4. No, there is no force or motion happening.
5. No, it is not in contact with anything which could give it energy.

17. PE = m x g x h remember…(gravity = 9.8m/s2)
POTENTIAL energy (PE)
Potential Energy (PE) is the stored energy of an object resulting from the position of the object in a system.
PE is measured by multiplying the mass of the object times the gravity and then times the height.
PE = m x g x h remember…(gravity = 9.8m/s2)
Units are Joules!!! (J)
1 Joule= 1kg x m2/s2

18. POTENTIAL energy (PE) Examples of objects with high PE:
A stretched rubber band
Any hanging object
Any compressed object (like a spring)
Any object that is high up

19. PE Power Triangle P m g h Plug PE = m*g*h into a Power Triangle
Write the equations when you solve for m and h. P E m g h

20. A mountain biker rides down a 42m high mountain with 2500 J of GPE
A mountain biker rides down a 42m high mountain with 2500 J of GPE. What is the mass of the mountain biker? D U F A S
PE=2500
m=?
g=9.8
h=42 J Kg
m/s m
PE=m*g*h
m= PE/(g*h)
m= 2500J/(9.8m/s * 42 m)
m= 6.07 kg

21. Think about the number line:
Scientific Notation
Think about the number line: + - -2 -1 1 2

22. Here’s what that means…
Scientific Notation
When you see a number like:
3.46 E-4 m Come up on your calculator…
Here’s what that means…

23. Scientific Notation 3.46 E-4 … The E-4 means x10-4
And here is how you translate that into a number.
The exponent (-4) tells you how many times to move the decimal point (4).
And because it is negative (-), to move it left!)

24. Scientific Notation So for 3.46 E-4 g
You will move the decimal point 4 times to the left. (negative is to the left on the number line!!!)
= g
Make sure you put units on it also!
= g

25. Scientific Notation Let’s practice:
Change 4.86 E3 kg into a regular number…
Need to move the decimal 3 times and to the right because the 3 is positive.
= 4860 and don’t forget units!
= 4860 kg

26. Scientific Notation YOUR TURN: ANSWERS: 1.) 9.325 E-2 m
2.) E4 kg
3.) x10-6 g
4.) x105 cm3
ANSWERS:
1.) m
2.) kg
3.) g
4.) cm3

27. Solving Energy Problemsh
pg 299 (1-4)
m = PE h = PE
g*h g*m
do this 1st
do this 1st

28. MASS kilo hecto deka gram deci centi milli kg hg dg g cg mg 1,000 100
kilogram
hectogram
dekagram
gram
decigram
centigram
milligram
1,000
100 10 1
0.1
0.01
0.001