Ch6_SteeleM

Chapter 6

** Lesson 2: Work, Energy, and Power **

 * a) Internal vs. External Forces**

S = Survey Q = Question R = Read R = Recite R = Review with mom
 * 1) Why do we categorize forces as either internal or external?
 * 2) What are external forces?
 * 3) What are internal forces?
 * 1) __Internal and External Forces__: The importance of categorizing a force as being either internal or external is related to the ability of that type of force to change an object's total mechanical energy when it does work upon an object.
 * 2) __External Forces__:
 * Applied force, normal force, tension force, friction force, and air resistance force.
 * **Nonconservative forces** - capable of changing the total mechanical energy of an object.
 * 1) __Internal Forces__:
 * Gravity forces, magnetic force, electrical force, and spring force.
 * **Conservative forces** - capable of changing the form of energy without changing the total amount of mechanical energy.


 * Electricity Activity**

__**Evaluate:**__
 * 1) Does the cost of electricity seem like a lot to you? Discuss this with your friends.
 * The cost of electricity is relatively expensive. However, it is not unreasonable.
 * 1) Keep in mind that this cost only reflects ten appliances. What do you think your total cost actually is? Are there major appliances that you may have excluded from your list of ten that would make a big difference?
 * To be honest, I don’t use many appliances. I don’t blow dry or straighten my hair, and don’t own many electronics. My total cost would only go up a little bit, due to the lights in my room and the basement family computer. I did not exclude any major appliances from my list that would make a big difference.
 * 1) If you think your consumption is a lot – what can you change? Do you need/should change?
 * I don’t think that my consumption is a lot. In fact, I make a conscious effort to shut the lights off when people leave them on.

__**Thoughts:**__ I really liked this activity. I sat down with my mom, dad, and brother, and helped them calculate their kWh per month. My brother, due to his excessive XBOX and computer usage, was responsible for the majority of the kWh cost per month. We talked about things we can all do to reduce our energy consumption. We collectively agreed upon shutting all lights off when leaving a room, and shutting the computer off (or setting a screen saver) when we leaving the house.