Ch6_MarguliesM

toc Chapter 6

Work Energy and Power Lesson 1a
Work: when a force acts upon an object to cause a displacement of the object. The key ingredients to work force, displacement, and cause.
 * Mechanical Energy**: when work is done upon the object, it gains energy and the energy acquired by the object upon which work is done is ME
 * Potential Energy**: the energy possessed by a body by virtue of its position relative to others, stresses with itself, electric charge, and other factors
 * Kinetic energy**: energy that a body possesses by virtue of being in motion
 * Power**: the ability to do something, energy that is produced by mechanical, electrical, and other means and used to operate a device

Work = force times displacement times cosine(theta)

The Work-Energy Relationship
Internal vs. External
 * There are certain types of forces, that when present and when involved in doing work on objects will change the total mechanical energy of the object
 * **External Forces (Nonconservative forces)**: applied force, normal force, tension force, friction force, and air resistance force
 * **Internal Forces (conservative forces)**: gravity forces, magnetic force, electrical force, and spring force
 * categorizing a force is related to the ability of that force to change an object's total mechanical energy when it does work upon an object
 * Net work is done by an external force, the Total Mechanical Energy (KE + PE) is changed
 * **Positive Work:** objects gain energy
 * **Negative Work**: objects lose energy
 * These gains or losses can be in the form of potential or kinetic energy
 * The work is equal to the change in mechanical energy of the object
 * when a force doing net work on an object is an internal force, the total mechanical energy (KE + PE) is constant
 * Energy changes form
 * capable of changing the form of energy without changing the total mechanical energy

1. PE to KE 2. PE to KE 3. KE to PE 4. KE to PE 5. PE to KE
 * Quick Quiz**


 * Positive work or Negative work is dependent on the force doing the work is directed opposite the objects motion

1. +, Kinetic Energy 2. +, Both 3. +, Kinetic Energy 4. -, Kinetic Energy 5. +, Kinetic Energy 6. +, Potential Energy
 * Quick Quiz**

Electric Bill Analysis


In total, I think my bill costs my parents a normal amount of money each day. These are normal appliances that everyone uses in my household and they are part of life. I think that I could save more money by not using all these appliances daily. Also, if I become more green and turn off lights, when I am not using them. Or if lights are not necessary because there is still daylight outside. Approximately, a dollar a day can add up and be quite expensive. Especially because I didn't account for my computer charger and other major appliances I use daily. It is important to conserve energy and to be aware of what lights I turn on in the house.