1. Work

2. WORK The transfer of energy through motion
Done when a force is applied to an object over a distance

3. TWO REQUIREMENTS FOR WORK
Something has to move
The motion MUST be in the same direction as the applied force

4. WORK = (Force) * (Distance)
CALCULATING WORK
WORK = (Force) * (Distance)
W = F*d

5. UNITS FOR WORK & ITS COMPONENTS
METRIC ENGLISH
Force Newton (N) Pound (lb)
Distance Meter (m) Foot (ft)
Work Joule (J) Foot-Pound (Newton-Meter) (ft-lb)

6. WORK EXAMPLE
A 900 N mountain climber scales a 100 m cliff. How much work is done by the climber?
F = 900N W = F*d
d = 100m W = (900N)*(100m)
W = ?? W = 90,000 J

7. POWER The rate at which work is done
The amount of WORK per unit of TIME
How fast you do your work

8. POWER CALCULATION
POWER = Work
Time
P = W t

9. UNITS FOR POWER & ITS COMPONENTS
METRIC ENGLISH
Work Joule (J) Foot-Pound
Time Second (s) Second (s)
Power Watt (W) Ft-lb/s
(Joule/Second)

10. POWER EXAMPLE
A small motor does 4000 J of work in 20 seconds. What is the power of the motor in Watts?
W = 4000 J P = W / t
t = 20 s P = 4000J / 20s
P = ?? P = 200 W

11. OTHER UNITS FOR POWER 1 Kilowatt (KW) 1000 Watts
Used for Larger amounts of Power (Electric)
Example: 2460 Watts = ________ KW

12. OTHER UNITS FOR POWER 1 Horsepower (Hp) Approximately 750 Watts
Used to describe the power of engines or machines
Example: 4500 Watt Engine = _____ Hp