Ch6_GirginL

toc Chapter 6: Work, Energy, and Power

=Work, Energy, and Power: Lesson 1; A= January 12, 2012

1. What are the essential ingredients for work to be done upon an object?
 * force
 * displacement
 * cause
 * examples are:
 * horse pulling a plow through the field
 * person pushing cart down aisle
 * person lifting a heavy backpack upon shoulder
 * There must be a displacement and the force must cause the displacement

2. What is the mathematics of work?
 * W = F x d x cosO
 * F = force
 * D = displacement
 * O = theta

3. What is the meaning of Theta? >
 * theta - the angle between the force and the displacement vector
 * common problems have a cart on an incline
 * a force is applied to a cart to displace it at constant speed
 * the force is always applied parallel to the incline

4. What is the meaning of negative work?
 * a force acting upon a moving object to hinder a displacement
 * examples:
 * car skidding to a stop
 * baseball runner sliding to a stop
 * the force acts in the direction opposite the objects motion in order to slow it down
 * It refers to the numerical value that results when values of F, d, and theta are s substituted into the work equation

5. What are the units of Work?
 * 1 Joule = 1 Newton*1 meter

6. How is Work calculated?
 * force*displacement*cosO