1. 3
Concepts in Physics

2. Center of Gravity
The point in the body or object that its weight is balanced around
Changes with movement as the position of the extremities is changed
Changes when weights or objects are attached to body
The lower the center of gravity, the more stable the object

3. Center of Gravity Changes With Changes in Body Position

4. Line of Gravity
An imaginary vertical line that runs through the center of gravity
An object is most stable when the line of gravity passes through its base of support

5. Line of Gravity Must Fall Within the Base of Support

6. Base of Support
The two-dimensional area between and including an object’s points of contact with the supporting surface
A larger base of support provides more stability than a narrow base of support

7. Changing Base of Support for Stability

8. Stability
An object is most stable when the line of gravity stays within the base of support.
The larger the base of support, the more stable the object.
Stability is greater when the base of support is positioned in alignment with the direction of force application.

9. Definitions Creep Structural fatigue Endurance limit; fatigue failure
Cumulative-trauma injuries vs. acute-trauma injuries
Friction

10. Use of Friction in Therapeutic Exercise

11. Definitions- Class Defined
Strength
Work
Power
Energy
Potential energy
Kinetic energy
(continued)

12. Definitions –Class Defined
Velocity
Acceleration and deceleration
Elasticity
Stress and strain
Hooke’s law
Stress-strain curve
(continued)

13. Definitions –Class Defined
Inertia
Acceleration and Momentum
Action-Reaction
1st-3rd class levers