Ch6_MillerJ

= Joey Miller Chapter 6 Wikispace = toc

Physics Classroom Lesson Work Energy and Power Lesson 1a 1/12/12:
__**Section A The Mathematics of Work:**__


 * Topic Sentence:** Work is when a force causes some kind of displacement, it can be found by multiply the force*displacement*cosine(theta) or F*d*cos(theta)

Work can be defined as when a force causes some sort of displacement

The formula below can be applied:



F is the force, d displacement, and the angle (theta)

The angle measure is defined as the angle between the force and the displacement.

Example:

When a force is exerted on an object at an angle, only a part of the force contributes to the horizontal displacement.

Negative work- forces that act in the opposite direction of the object motion

theta is 180 degrees; cos 180 = -1 so a negative value results for the amount of work done upon the object

__**Section 2 Calculating Work:**__


 * Topic Sentence:** Work= force•displacement•cosine(theta)

When a force acts to cause an object to be displaced, three quantities must be known in order to calculate the work.

Those three quantities are force, displacement and the angle between the force and the displacement.

The work is subsequently calculated as force•displacement•cosine(theta) where theta is the angle between the force and the displacement vectors.

Electric Bill Activity:
__**Chart:**__



__**Sample Calculations:**__





__**Conclusion Paragraph:**__

In my opinion the cost of kWh is very reasonable. The cost for kWh varies based on consumption so some people may pay slightly more or slightly less than my family. It is also important to consider any price variations that may occur based on season, demand, or just increases in general. Just about everything we use consumes electricity, with that in mind I think that electric prices are reasonable. The ten appliances I chose do not reflect my and my families main consumption. Some of the large things I excluded are the two refrigerators that run 24/7, the pool (summer only), the sub-pump, and various other electronics that draw power throughout the day. One of the reasons our electric bill is lower during the school year is because we aren't home the majority of the time. We all leave for school/work and don't return until late that night. The major thing I think that all people need to consider is not the cost but the effect the electric generation has on the environment. If all people cut their energy consumption than the coal burning power stations would have to burn less coal because there was less of a demand for energy. When I calculated my energy use for the day I expected it to be higher than it was. I guess because the electronics I own are newer they are more energy efficient and consume less electricity that I had previously thought.