(Chapter 5, Section 1)
·
Work =
the transfer of energy that occurs when a force makes an object move
(measured in Joules)
o
Two conditions
for work:
§ The object must move
§
Movement in the same direction as the applied force
·
Picking up books à Work is done
·
Carrying books
down the hall à no Work
o
When work is
done, energy is always transferred
§
Example: lifting
an object
·
Its energy (GPE)
increases
·
Your energy (CPE)
decreases
o
If you move
an object a greater distance, you do more work. If it takes
more force to move an object, you do more work.
To calculate work:
§ W = F * d
· W = work
· F = force
· d = distance
o
Note: work is
only being done WHILE the force is being applied
·
Power =
the rate at which work is done, or the rate at which energy is transferred (measured in
o
The faster you
do the work, the more power is used.
Power = W/ t Power = E/t
o
W = Work; E
= Energy
o
t = time
