Monday Jan 3:

Key Concept(s) Today: Snell's Law & Review: 

Journal: Define "Conservation of Energy"

Review:

 

Conservation of Energy

Energy cannot be created nor destroyed. The one exception is in nuclear reactions where mass is turned into energy, and as we have seen, this occurs only in the center of stars and in nuclear reactors.

Let's look at an example of an electric light bulb. A light bulb changes electrical energy into light energy. If we were to measure these energies for one second, we might get energy numbers that look something like this:     Electrical Energy In 100 J (joules) Light Energy Out 70 J (joules)   This would suggest that energy is not conserved? Where did the other 30 J of energy go? Remember that energy can change into more than one form simultaneously. And if you feel a light bulb it is very hot. The "missing" energy must have gone into heat energy. So, the actual energies were more like this:   Electrical Energy In 100 J (joules) Light Energy Out 70 J (joules) + Heat Energy Out 30 J (joules)   http://fi.edu/guide/hughes/energyconservation.html

1. A pendulum (length = 50m) was released 30m above the lowest ("rest") point. What would be the speed at the "rest point?

Answer:

PE = KE

mgh = ½ mv²

 ^{1(10)(30) = 1/2(1)(}v²⁾

^{V = 24.5 m/s}

Film: Fat Man & Little Boy

L#31: Q's: 1 - 3, 5, 6, 8-1, 16,19  Due Wed Jan 5 (Snell's Law)

L#32: Q's: 1- 8, 10, 11, 13, 16, 20  Due Thurs Jan 6 (Gas Law)

Tower Contest Friday 7 Jan:

L#33: Q's: 1- 7, 9, 10, 12 - 14, 19,  Due Mon Jan 10 (Two Body Tension)

Lab: Egg Strength (Tues 11 Jan)

L#34: Q's: 1- 10, 12 - 16, 19  Due Wed Jan 12 (Color)

L#36: Q's: 1, 2, 3 - 12, 19, 20  Due Fri Jan 14 (Archimedes)

Lab: Archimedes (Tues 18 Jan)

Review Wed 19 Jan

Test Thurs 20 Jan (L # 31-36)