1. Center of Gravity
Chapter 10

2. Center of Gravity (CG)
The point located at the object’s avg. position of weight.
Seems as though all the weight is concentrated around this point

3. Center of Gravity Uniform object: at the midpoint
Baseball at the center
Irregularly shaped object
Bat is near the heavier end
Discuss hammer

4. Motion
Projectile
parabolic path of its center of gravity
Hammer toss

5. Motion
Projectile
wobble around its center of gravity because cg is off center
Example: Sun and stars
as the system orbits, the cg is displaced

6. Motion
Smooth Path
straight line motion of its center of gravity pg. 137
rotation around its center of gravity
Hammer slide across floor

7. Locating CG Uniform Object
Can be found by suspending an object by two or more points and looking at the lines of intersection
Uniform Object
CG is a balance point
supporting that single point supports the entire object
Can be located where no material exists - doughnut
Hewitt

8. Toppling CG must be over the base in order to not tip over Examples
Leaning Tower of Pisa
Chair demo
Monkeys - tail allows a shift in the cg and increase stability
CG must be over your feet for you to be stable

9. Toppling Demos Pick up the money Stand up! Up against the wall!
Monkeys/Dinosaurs

10. Stability Center of gravity seeks lowest point
Stable – if displaced, cg goes up
Unstable - if displaced, cg goes down
Neutral – if displaced, cg the same