Levangi and Norkin pg.19-38

Newton's Law of reaction

For every action, there is an equal and opposite reaction. (REACTION FORCES)

Linear force graph comprehension

Forces applied up (y-axis), forward or anterior (z-axis), or to the right (x-axis) will be assigned positive signs, whereas forces applied down, back or posterior, or to the left will be assigned negative signs. The magnitudes of vectors in opposite directions should always be assigned opposite signs.

equilibirum

balance static equilibrium: motinaless dynamic equilirum: moving-- either linear or rotary

torque (moment of force)

force rotates an object around an axis. (joints produce torque force)

concurrent forces:

forces that all go through one point of intersection

Tensile forces

opposite pulls on the same object. if object cannot handle tensile forces it will break same thing as joint distraction (PT langauge)

friciton

the force resisting the relative motion of solid surfaces. Coefficent factors: rubber aginst ruvbber versed wood against waxed force. Normal: force that going against the big force.

Joint Distraction

the pull or movement of one boney segment away from another essentally a joint being pulled apart same thing as tensile forces (biomechanic language)

Law of inertia

the tendcy to do nothing, remain unchanged. (nothing moves unless a force is acted on it)

shear force

unaligned forces pushing one part of a body in one direction, and another part of the body in the opposite direction.

linear force system:

whenever two or more forces act on the same segment, in the same plane, and in the same line muscles produce linear force (makes sense if you think about sarcomeres)