1. WORK The Transfer of Energy
How does the previous investigation help us to understand how forces transfer energy?

2. The Transfer of Energy is called WORK
Work measures the effects of a force acting over a distance.
Work = F*d so…
Work= energy transferred
The units are N * m = Joules (J)
1 Joule= 1kg x m2/s2
(F) * (d) = Work
(1kg x m/s2 x m)= 1kg x m2/s2

3. Work and Power Warm Up
1. Who does more work - a man who lifts a large box from the ground up into the back of a truck, or a man who puts the same box on a trolley and wheels it up a ramp into the truck? A the man who lifts it B the man with the trolley C they do the same work

4. Work and Power Warm Up
1. Who does more work - a man who lifts a large box from the ground up into the back of a truck, or a man who puts the same box on a trolley and wheels it up a ramp into the truck? A the man who lifts it B the man with the trolley C they do the same work

5. Work and Power Warm Up
2. Energy and work use the same unit of the Joule because: A that is the unit chosen by the scientist named Pascal who studied heat B energy is required to do work C both measure the speed at which power is used

6. Work and Power Warm Up
2. Energy and work use the same unit of the Joule because: A that is the unit chosen by the scientist named Pascal who studied heat B energy is required to do work C both measure the speed at which power is used
Complete problems Then have them checked!

7. Think about light bulbs!
POWER
What’s Power?
Power = how much work is done in a given amount of time.
Does running require more work than walking the same distance?
No! So what is the difference between running and walking?
A: The time it takes!!!
So we need to account for the time it takes to do work… the equation that measures that is
P = W (Units for Power are Joules = Watts)
t sec
Think about light bulbs!

8. POWER in DUFAS
While running track, Drew’s legs do 5780J of work in 183sec. What is his power output?
2. The chain that is pulling a rollercoaster up the first hill does 24652J of work over a 79sec time interval. What is the power output of the chain?
3. It takes Ms. Webb 20s to apply 23N of force to lift a box 5m. What was her power output?

9. POWER Problems pg. 287 (1-3)
Complete on Classwork DUFAS chart and then have them checked!

10. Methods of Energy TRANSFER

11. Energy TRANSFER:
Energy transfer - is how the same type of energy is passed from one object to another object.
There are only THREE ways that energy can be transferred between objects…

12. Energy TRANSFER: Method 1: Conduction
The transfer of energy through matter by direct contact of particles.
Examples: a pot on a stove, a metal spoon in a bowl of hot soup, wires carrying electricity, friction/air resistance transforms energy to heat.

13. Energy TRANSFER: Method 2: Radiation
The transfer of energy in the form of a wave. (mechanical or electromagnetic waves)
Examples: How Earth gets it’s energy from the sun, a microwave oven cooking food, sound.

14. Energy TRANSFER: Method 3: Convection
The transfer of energy by the movement of gases or liquids. (fluid movement only!!!)
Hot fluids will rise while cold fluids will sink… this creates a swirling motion.
Examples: Hurricanes, pasta or rice swirling in boiling water, a hot air balloon.

16. Forces That Transfer Energy Making Crash Barriers

20. Crumple Zones

21. Collapsed Crumple Zone

22. Good Crumple Zone

23. Investigating How Forces Transfer Energy Part A: Creating a Barrier
Focus Question: What barrier design will stop the car in the shortest distance?
Your task is to create a stopping barrier out of dominoes that will stop the car in the shortest distance possible.

24. Your Mission… You will answer the pre-lab questions
(1-4) BEFORE you start the lab.
2. Practice three or four times before
you record your trials.
3. You will stack the dominos at the 60cm
mark on the ramp.
4. Draw your design in your table.
5. Record the distance in cm from the 60cm mark to the first domino.
6. If your dominos touch the end wall, your trial doesn't count!
7. You can not have any dominos touching the black wall at the end of ramp.