1. Mechanical Energy http://www.youtube.com/watch?v=qZ4FFWvZtyo

3. Mechanical Energy Mechanical energy – the sum of the kinetic and potential energies Em = Ep + Ek

4. Law of Conservation of Energy Energy cannot be created or destroyed, only transferred. – E p transferred into E k when an object moves

5. Energy transformed from one type to another, BUT the TOTAL AMOUNT OF ENERGY never changes. Amount of mechanical Energy is constant! To make our life simple, we will assume that no energy is lost to heat/friction/air resistance etc (even though in real life it is )

7. Example 6.7

8. A 1.5kg block is dropped off a cliff, 30.0m above the surface of the lake. What is the velocity just before it hit the water?

9. Remember that work is change in Energy! Let’s watch a highly questionable activity and link it to Energy! DON’T ATTEMPT THIS AT HOME!

10. An average force of 100.0N is needed to pull a bow string back 0.500m. The bow is aimed straight up in the air and released. a)What is the work done to pull the bow string back? b)How much elastic potential energy is stored in the bow? c)How much kinetic energy does the arrow have just as it leaves from the bow? d)What will be the E k and E P at the arrows highest position? WHAT IS THE RELATIONSHIP BETWEEN W, Ep & Ek???

11. Practice Pg. 183 # 8-10 Pg. 184 # 11-12 Pg. 186 # 13-14 Pg. 188 # 1-3, 5-9