1. Bellwork Why don’t you want your egg to bounce for the project?
Because, it may hit the hard ground and crack / break.

2. Today’s Agenda Follow-up on this week’s lab Momentum and Impulse notes
Egg Drop Analysis
Momentum and Impulse and the Egg Drop
Sports Figures Video
Next homework assignment

3. Work and Power Lab Follow-Up
1/10/14

4. Follow-up Questions (in your notes)
How can a large force result in relatively small power?
How can a small force result in relatively large power?

5. Follow-up Questions (in your notes)
[Combining Work and Power equations]

6. Follow-up Questions (in your notes)
Force and distance are directly proportional to power
Time is indirectly proportional to power

7. Follow-up Answers (in your notes)
If the force is done over small distances and/or a long period of time
If the force is done over large distances and/ or a short period of time

8. Follow-up Answers with values
Example: F = 5500 N; d = m and t = 3600 s is…
P = W
Example: F = 5.5 N; d = 1500 m and t = 0.36 s is…
P = 23,000 W

9. Momentum and Impulse Notes
1/10/14

10. Pre-Quiz (8 True/False Questions)
Impulses are normally smaller when bouncing takes place.
If a net force acts on an object, the object's momentum will change.
Momentum is defined as an object's mass times its velocity.
If the net external force acting on a system is zero, then the total momentum of the system is zero.

11. Pre-Quiz
Impulse is defined as the force exerted on an object times the time it lasts.
Automobile seatbelts are used to lengthen the time of impact in case of a collision.
When a baseball player follows through when hitting the ball, the contact time with the ball is longer.
The momentum of a large truck at rest is greater then the momentum of bee flying across the room.

12. Pre-Quiz Answers
Impulses are normally smaller when bouncing takes place. FALSE
If a net force acts on an object, the object's momentum will change. TRUE
Momentum is defined as an object's mass times its velocity. TRUE
If the net external force acting on a system is zero, then the total momentum of the system is zero. FALSE

13. Pre-Quiz Answers
Impulse is defined as the force exerted on an object times the time it lasts. TRUE
Automobile seatbelts are used to lengthen the time of impact in case of a collision. TRUE
When a baseball player follows through when hitting the ball, the contact time with the ball is longer. TRUE
The momentum of a large truck at rest is greater then the momentum of bee flying across the room. FALSE

14. Momentum and Impulse Momentum (vector): An object that is in motion
Unit: kg · (m/s)
Impulse (vector): The time and amount of force acting on an object
Unit: N · s

15. Momentum and Impulse Impulses change the momentum of objects
The longer the force acts on an object the greater the momentum change (following through on a swing)
Extending impact times decreases the force (air bags and seat belts)

16. Momentum and Impulse
In a collision, an object experiences a force for a given amount of time that results in its mass undergoing a change in velocity.
Impulse = change of momentum
F · t = Δ (m · v)

17. Egg Drop Analysis Individual – everyone needs to do the analysis
Due Monday 1/27/14

18. Save an egg, crack a smile!

19. Oh no, Mr. Bill!

20. Momentum and Impulse and the Egg Drop Project
F · t = Δ (m · v)
You can not change the mass (m)
You can not change the velocity (v)
But you can try to change the time (t)
So, what will this do to the force (F)?

21. F · t = Change of momentum
Egg vs. Tile Floor
F · t = Change of momentum

22. Egg vs. Grass
F · t = Change of momentum

23. F · t = Change of momentum
Egg Drop Project
F · t = Δ (m · v)
Your goal is to maximize the time!
F · t = Change of momentum
F · t = Change of momentum

24. Video

25. Homework
IMPORTANT!!! If given the mass in kg you need to find the weight (Fg) of the object!
Work and Power Problems
Due Tues. 1/14/14