1. Work and Power

2. Work Work is exerting a force over a distance
For work to be done the object in question must be moved
When a table is pushed and moved has work been done on the table?
YES!!!
What if the table failed to move, was work done on the table then?
NO!!!

3. Work
Also the object must move in the direction of the force for work to occur
Suppose I lift up a book bag and walk with it, is work being done to the book bag?
No, because the direction of the force (up) did not match the motion of the object horizontal
Not all the force has to be in the direction of motion for work to occur, just part of the force (or a vector of the force)
However, when the direction of the force perfectly matches the motion of the object, this is the most efficient kind of work

4. Work Formula
Work = Force x Distance
The unit for work is the Joule (J)
Suppose I apply 150N force to a table the slides 8m, how much work has been done on the table?
150N x 8m = 1200J

5. Power Power is the rate (or how fast) work can be done.
In order to increase power, the work must be done faster
Think about a particular job, lets say shoveling snow
If you go out there with a snow shovel it may take 2 hours to clear off your drive way
Now suppose you use a snow-blower and the same task now takes 30 minutes
The same work has been done, but the power was increased with the snow blower because the rate of work was faster

6. Power Power = Work / Time The unit for power is the Watt (W)
This means for a 40W light bulb to stay lit for 1s requires 40J of power
James Watt also used horse power (hp)
1hp is equal to about 746 W
This was used as a comparison for the 1st steam engines to show how much stronger than a horse they were