1. Do Now:
1. A 9000 Newton car is traveling on dry concrete at constant velocity. Calculate the force required to keep it moving.

2. Aim: How is Power defined?
HW:

3. How can we calculate work from a graph?
Force vs Displacement
On a force vs displ. Graph
Area under line equals work. 10 8 6 4 2
Force (N)
Displacement (m)

4. Calculate work Force vs Displacement 10 8 6 Force (N) 4 2
Displacement (m)

5. How does the jeep make it up the hill?
Jeep Climbing
How does the jeep make it up the hill?
What was another way for the jeep to reach the top of the hill?
How is this way different?

6. Definitions Power Units Amount of WORK DONE PER UNIT TIME
Joule/second (J/s)
-OR-
Watts (W)

7. Envelope Activity
With your table work on the following 3 problems.

8. A power plant produces 300 mega joules of energy in 30 seconds
A power plant produces 300 mega joules of energy in 30 seconds. How much power does the plant produce?
A team of dogs pulls a sled with an average force of 3000 Newtons across a distance of 200 meters in 75 seconds. How much power do the dogs produce?
A motor pulls an 8000 Newton elevator upward at an average speed of 3.0 meters per second. How much power is used by the motor?

9. Power Plant
A power plant produces 300 mega joules of energy in 30 seconds. How much power does the plant produce?

10. Dog Sled
A team of dogs pulls a sled with an average force of 3000 Newtons across a distance of 200 meters in 75 seconds. How much power do the dogs produce?

11. Elevator Motor A motor pulls an 8000 Newton elevator upward at an
average speed of 3.0 meters per second.
How much power is used by the motor?
How can the demand for power from the motor be
reduced?
Pull the cars up at a slower speed or
Use lighter elevator cars.

12. Real Life Application ONLY 53,000 dollars! $$$$$$$$$$$$$$$$
Horse Power (hp) is another unit for power.
1 hp = 746 Watts
Originally used to compare power of steam engines to work horses.
Example: 2014 Porsche Cayman has 325 hp
ONLY 53,000 dollars!
$$$$$$$$$$$$$$$$

13. Summary Definition of Power? 2. Equations for Power?
3. Units for Power?