1. Mr. Chainani Who’s the new guy?!? I’m from Hong Kong
I studied Physics at University
I’ll be teaching you today…

2. What’s with the Red and Green Cards?!
Traffic Lights
Green  I’m all good
Red  I don’t quite understand what's going on. HELP!

3. Energy and Work Done

4. What’s on the menu today?
Memory Jog  What concepts about energy do you remember?
“Work Done”
Define and use the equation
Answer some questions together  Some Exam Technique
Answer some questions in groups
Then go through together

5. Memory Jog In groups / tables on mini-white board
Write down all the keywords and ideas you can remember about energy and energy transfer
Hold your mini whiteboards up when you are done
You have 3 minutes!

6. Mechanical (“Kinetic”)
Key Ideas about Energy
Why potential? What exactly does that mean?
Potential
Gravitational
Chemical
Nuclear
Elastic/Strain
Kinetic
Mechanical (“Kinetic”)
Light
Sound
Electrical
Thermal

7. Probably the most Important Concept in Physics
Conservation of Energy
Energy can neither be created nor destroyed; rather, it transforms from one form to another.
…this is the basis of almost all physics and you will use it well into university and beyond

8. How do we quantify energy?
Units of Energy are
Joules (J)
James Prescott Joule 1818 – 1889 English physicist
 and brewer

9. How can we visualise energy transfers?

10. What are equivalent units of Joules?
Work Done
What are equivalent units of Joules?

11. Exam Technique
Read
Extract
Equation
Solve
Units

12. Work Done – Example #1 Read Extract Equation Solve Units
A box with a rope tied to it is dragged 2 meters across the floor with a force of 10 Newtons.
What is the work done?
Read
Extract
Equation
Solve
Units

13. Work Done – Example #2
A car engine produces 75 Newtons of force and does 525J of work.
How far has it travelled?
Does anyone know which car this is? Why is it special?
Why is it important to understand work done?
Think about energy transfers.

14. Work Done Question: Let’s look at the following video:
If no distance is travelled, am I doing work?
Am I expending energy?
Let’s look at the following video:

15. In order for Work to be done
Work Done
In order for Work to be done
…there must be a displacement…a distance must be travelled
Work done is a measure of the transfer of energy

16. Questions!

17. Section 1 Look at Section 1 of the worksheet
In your groups, try and answer the questions
Use your traffic lights placed on the table if you are having trouble

18. Section 2 These are more challenging questions
Have a go and see how you do

19. Summary There are 9 types of Energy Energy is measured in Joules
Energy is Conserved
WorkDone = Force x Distance in direction of force
WorkDone is a measure of the transfer of energy and is measured in Joules
No work is done if there is no distance travelled