2. HW DUEN/A Tonight’s HWRead & Study 8.3-8.6; do # 6-13 p. 119 Do Now20 minutes to work on your labs – GO!

3. 10 minutes to complete #1-5! Plug in and turn on the PASCO touch screens Follow the prompts to open the temperature sensor field (should be automatic)

4. The temp… A. Increased B. Decreased C. Stay the same

5. Volunteers to share?

6. When work is done to raise a bowling ball, the bowling ball acquires the ability to do work on an object it hits when it falls. 9.3 Mechanical Energy

7. When work is done to wind a spring mechanism, the spring acquires the ability to do work on various gears to run a clock, drive a car, ring a bell, or sound an alarm. 9.3 Mechanical Energy

8. Keep adding to this…

9. Look at this:

10. 8.4 POTENTIAL ENERGY, aka PE (pgs 106-107) An object may store energy by virtue of its position This energy that is stored and held in readiness is called potential energy (PE) In other words, this PE has the potential of doing work on something Examples: Compressed spring or stretched rubber band (tension) Electrical energy (battery) Gravitational potential energy Grav. PE = mgh The amount of gravitational potential energy possess by an object is equal to the work done against gravity in lifting it.

11. 8.5 KINETIC ENERGY, aka KE (pg 108) KINETIC ENERGY IS NOT MOMENTUM! If an object is moving, then it is capable of doing work It has energy of motion, or KINETIC ENERGY The KE of an object depends on its mass and on its speed KE = ½ m v 2 The KE of a moving object is equal to the WORK required to; Bring it TO that speed, from rest….or The work the object CAN do while being brought to rest.

12. The WORK-ENERGY THEOREM THEN… ENERGY changes IF… WORK Is done THEN…

13. Like a wrecking ball! Not this one!!!! (That’s a train wreck)

14. Like a wrecking ball! This one!

15. Look at this:

16. Graphic Organizer (WRITE THIS!) THEN… ENERGY changes IF… WORK Is done THEN… W = ΔE

17. Graphic Organizer (WRITE THIS!) THEN… ENERGY changes IF… WORK Is done THEN… W = ΔE Mechanical Energy (M.E) Potential Energy (P.E) Kinetic Energy (K.E)

18. Do #1-9!

19. P.E

20. K.E

21. In addition to… Work Energy Theorem Work Energy Theorem (both as a formula and in words, pg 108)  Work changes energy  If there is no change in energy, then no work is done Work = the change in energyW = ΔE

22. In addition to… Work Energy Theorem And the different types of PE & KE Work Energy Theorem (both as a formula and in words, pg 108)  Work changes energy  If there is no change in energy, then no work is done Work = the change in energyW = ΔE

23. In addition to… Work Energy Theorem And the different types of PE & KE There is one more MAIN CONCEPT for today… Work Energy Theorem (both as a formula and in words, pg 108)  Work changes energy  If there is no change in energy, then no work is done Work = the change in energyW = ΔE

24. Law of Conservation of Energy 8.6: Conservation of Energy (p. 109-111)  Energy itself cannot be “seen,” but the effects of it can be observed when energy… o TRANSFORMS from one FORM to another, o Or TRANSFERS from one OBJECT to another  Energy cannot be created or destroyed – only transformed or transferred.  The TOTAL ENERGY AMOUNT does not change. TOTAL MECH. ENERGY = TOTAL P.E. + TOTAL K.E. ∑ M.E. = ∑ P.E. + ∑ K.E.

25. MFMcGrawCh07 - Energy - Revised: 2/21/1025 Conservation of Energy Example: Energy transforms without net loss or net gain in the operation of a pile driver.

26. Part of the PE of the wound spring changes into KE. The remaining PE goes into heating the machinery and the surroundings due to friction. No energy is lost. Conservation of Energy

27. Everywhere along the path of the pendulum bob, the sum of PE and KE is the same. Because of the work done against friction, this energy will eventually be transformed into heat. Conservation of Energy

29. 5 MINUTES TO COMPLETE:

30. 3 are set up for you…

31. Now try this!