3 Concepts in Physics

Center of Gravity The point in the body or object that its weight is balanced around ________________________________ ________________________________ Changes when weights or objects are attached to body ______________________________ _____________________________

Center of Gravity Changes With Changes in Body Position

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

Line of Gravity Must Fall Within the Base of Support

Base of Support The two-dimensional area between and including an object’s points of contact with the supporting surface ______________________________ _______________________________ ______________________

Changing Base of Support for Stability

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.

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

Definitions Strength Work Power

Use of Friction in Therapeutic Exercise

Definitions- Class Defined Physiological Muscle Advantages Multi-joint Muscles Summation of Forces Energy Potential energy Kinetic energy (continued)

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

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