Ch6_AronskyA

toc =Lesson 1: Work, Energy, and Power = Newton's laws serve as a useful model for analyzing motion and making predictions about the final state of an object's motion. When a force acts upon an object to cause a displacement of the object, ** work ** was done upon the object. There are three key //ingredients// to work - force, displacement, and cause. There are several good examples of work - a horse pulling a plow through the field, a father pushing a grocery cart down the aisle of a grocery store, a freshman lifting a backpack full of books upon her shoulder. In each case described, there is a force exerted upon an object to cause that object to be displaced.  W= F*d*cos** θ ** where ** F ** is the force, ** d ** is the displacement, and the angle is defined as the angle between the force and the displacement vector. **// To Do Work, Forces Must Cause Displacements //** A vertical force can never cause a horizontal displacement; thus, a vertical force does not do work on a horizontally displaced object!!  When a force is exerted on an object at an angle to the horizontal, only a part of the force contributes to a horizontal displacement. **// The Meaning of Theta //**  Theta is ALWAYS defined as the angle between the force and the displacement vector. **// The Meaning of Negative Work //** On occasion, a force acts upon a moving object to hinder a displacement. Examples might include a car skidding to a stop on a roadway surface or a baseball runner sliding to a stop on the infield dirt. In such instances, the force acts in the direction opposite the objects motion in order to slow it down. The //negative// of negative work refers to the numerical value that results when values of F, d and theta are substituted into the work equation. Since the force vector is directly opposite the displacement vector, theta is 180 degrees. The cosine(180 degrees) is -1 and so a negative value results for the amount of work done upon the object. ** Units of Work ** The standard metric unit is the ** Joule ** (abbreviated ** J **). One Joule is equivalent to one Newton of force causing a displacement of one meter( 1J= 1N*m) Any unit of force times any unit of displacement is equivalent to a unit of work. In summary, work is done when a force acts upon an object to cause a displacement. Three quantities must be known in order to calculate the amount of work. Those three quantities are force, displacement and the angle between the force and the displacement.
 * <span style="font-family: Tahoma,Geneva,sans-serif;">Definition and Mathematics of Work **

=<span style="font-family: Tahoma,Geneva,sans-serif;">Power Costs Activity =



<span style="font-family: Tahoma,Geneva,sans-serif;">**Total Dollar Amount Due:** $101.63 <span style="font-family: Tahoma,Geneva,sans-serif;">**kWh Consumed that Month:** 595

<span style="font-family: Tahoma,Geneva,sans-serif;">**Average Cost per kWh:** $0.1708 <span style="font-family: Tahoma,Geneva,sans-serif;">**Value on Electric Bill:** $0.109143
 * <span style="font-family: Tahoma,Geneva,sans-serif;">Comparing the two costs: the average cost value is higher than that of the electric bill value because it includes service and distribution charges. This way, PSE&G makes a profit for themselves.

<span style="font-family: Tahoma,Geneva,sans-serif;">**What I Cost my Parents per day:** <span style="font-family: Tahoma,Geneva,sans-serif;">

<span style="font-family: Tahoma,Geneva,sans-serif;">**Evaluate**: <span style="font-family: Tahoma,Geneva,sans-serif;">**1. Does the cost of electricity seem like a lot to you?** <span style="font-family: Tahoma,Geneva,sans-serif;">**2.** **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?** <span style="font-family: Tahoma,Geneva,sans-serif;">**3. If you think your consumption is a lot - what can you change? Do you need/should change?**
 * <span style="font-family: Tahoma,Geneva,sans-serif;">Yes because this amount is only for just a day. The cost adds up each month, making electricity very expensive per year. This is also excluding air conditioning during the summer time and several appliances that we use in the household, so over time the cost becomes higher and higher.
 * <span style="font-family: Tahoma,Geneva,sans-serif;">I left out the washer and dryer, the dishwasher, actual lighting, computers, and telephones. Therefore, I think the total cost is much higher because those appliances are used often throughout the day, making a great difference.
 * <span style="font-family: Tahoma,Geneva,sans-serif;">Some changes that could be made include unplugging appliances when not in use, buying energy efficient products, and always turning off the lights. I am guilty because I leave my telephone and computer chargers plugged into the outlets and sometimes forget to turn off the lights. I definitely need to be more conscious of my actions to become more energy conservative.

<span style="font-family: Tahoma,Geneva,sans-serif;">**Conclusion**: <span style="font-family: Tahoma,Geneva,sans-serif;">Before doing this activity, I never considered the actual cost of electricity. I took it for granted and used it freely. Now I see how everything adds up to a lot of money on top of a universal electric consumption. I feel its necessary to cut down on energy usage and make a conscious effort energy smart. As my mom and I discussed, we realized that we can find easy ways to reduce waste!