1. "I think that was the game we discovered Gary Russell as a potential short-yardage and goal-line runner," Tomlin said. "And that's been solid for us. We don't pretend that it's something mystical. We've just got to formulate good plans, call good plays and execute them."
Tomlin called Russell "a one-trick pony. He's down hill. It doesn't matter what play you call for him. It's down hill. That happens to be a positive attribute for those circumstances."
Russell, signed as an undrafted rookie in 2007, is no Bus. But, at 5-11, he is stocky and heavier than his listed 215 pounds.
"Very rarely is he knocked back," Tomlin said. "He's got a nice center of gravity."

2. ROTATIONAL MECHANICS

3. What causes rotation? Force?
Let’s name it…
Torque
Pick a letter to represent it…
Tau
How do we calculate it?
Well…what makes it easier or more difficult to rotate an object?
Why is a doorknob always in the same spot?

4. Torque=Force (perpendicular) times Lever Arm
Think about it!
Ever use a wrench?
Torque=Force (perpendicular) times Lever Arm

5. How can a see-saw be balanced?

6. Which object will roll the fastest?

7. What is rotational inertia?
Compared to linear inertia?
Resistance to changes in rotational motion
An object rotating about an axis tends to keep rotating about that axis.

8. What does rotational inertia depend on?
What did inertia depend on?
The greater the distance between the bulk of the mass of an object and the axis about which rotation takes place, the greater the rotational inertia (Baseball Bat)
Rotational inertia also depends on the distribution of the mass!

9. Rotational Inertia
The farther the mass is from the axis…the less likely the object is to rotate.

12. Angular momentum equals rotational inertia times angular velocity
What was momentum before?
Linear
p=mv
What is angular momentum?
“inertia of rotation”
Angular momentum equals rotational inertia times angular velocity

13. Angular Momentum
An object or system of objects will maintain its angular momentum unless acted upon by an unbalanced external torque.

14. Angular Momentum There is another way to calculate angular momentum.
Can you help me?

15. Law of Conservation of Angular Momentum
If no unbalanced external torque acts on a rotating system, the angular momentum of that system is constant.
Iω=Iω

16. Who spins faster? Why?

17. Why does a top tip over?