Ch6_KwarkR

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=Summary: Lesson 1= Part A 1)What is work? Work is when a force causes an object to have displacement. 2)How would you calculate work? where **F** is the force, **d** is the displacement, and the angle ( **theta** ) is the angle between the force and the displacement vector.

3)I know what work is, but what is negative work? Negative work is if instead of causing something to move, something hinders the object's displacement. For example, when the force vector is directly opposite the displacement vector, like a car skidding to a stop (the friction force of the brakes causes the wheels to stop rotating, causing the car to slow down).

4)What is the unit for work? The unit is Joules, or Newton-meters.

=Summary: Lesson 2= Part A 1)What are internal and external forces? Internal forces are non-contact forces like gravitational, spring, magnetic, and electrical forces. External forces are applied forces like normal, tension, and friction forces. 2)How does a force change total mechanical energy of an object when work is done? -Positive work means the object gains energy. Displacement and force point in the same direction. -Negative work means the object loses energy. Displacement and work point in opposite directions. -When only internal work is done, KE+PE=constant (the entire system's energy is the same, just in different forms). This is called energy conservation.

In-Class Questions: 1. PE to KE 2. PE to KE 3. KE to PE 4. KE to PE 5. PE to KE 6. +, KE 7. +, Both 8. +, KE 9. -, KE 10. +, KE 11. +, PE

Activity: Analysis of Energy Bill Total: 25.5442 kWh
 * Item: || KiloWatts Consumed || Hours used per Day || kWh used per Day ||
 * Microwave || 1.2 || .1 || .12 ||
 * Blow Dryer || 1.0 || .05 || .05 ||
 * Macbook || .08 || 10 || .8 ||
 * Toaster || .90 || .05 || .045 ||
 * Digital Clock || .005 || 24 || .12 ||
 * Washing Machine || .450 || .00248 || .001116 ||
 * Dehumidifier || .460 || 4 || 1.84 ||
 * Space Heater || 1.5 || 8 || 12 ||
 * Refrigerator || .44 || 24 || 10.56 ||
 * Dryer || 2.7 || .002976 || .008035 ||

Total Amount Due: $105.64 Total KWH Usage 30 days: 574 Actual cost per kWh=12.1 cents per kWh 25.5442 x .121 = $3.09 Cost per month: 3.09 x 30 = $92.73
 * Electric Bill Analysis: **
 * The number above includes fees and charges.

-This seems really accurate. I only excluded the light bulbs and the TV, so the $13 difference between my calculated cost and the actual cost can be accounted for. These appliances are usually all the electricity we use in our household. My calculated cost is not much at all, considering appliances like the refrigerator and the dehumidifier are for the entire family, not just me. I can cut down on electric usage by turning on my space heater for less time and also trying to use all my appliances less in general

This activity really enlightened me about the energy bill and about energy we use every day. I never knew what an energy looked like before today, and I learned the important things on it. It was cool figuring out what I cost my parents monthly, and I realized that I have to cut down on my electric usage, especially by turning off the lights whenever I leave the room.