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A abduction

Movement of a segment in the frontal plane away from the midline of the body


The rate at which velocity changes


Movement of a segment in the frontal plane toward the midline of the body

afferent neuron

Neuron that carries impulse toward the central nervous system; sensory neuron


Muscle primarily responsible for motion; prime mover

angle of attack

The angle between the long axis of a projected object and the direction of airflow

angle of incidence

The angle at which an object strikes a hard surface

angle of projection

The angle between the horizontal and the initial velocity vector of a projectile

angle of pull

The angle between the mechanical axis of bone and the line of pull of a muscle

angle of reflection

The angle at which an object will leave a hard surface after striking it

angular acceleration

The rate at which angular velocity changes

angular displacement

Any change in angle

angular impulse

A torque applied over some period of time

angular momentum

The quantity of angular motion a lever possesses, equal to the product of the moment of inertia and the angular velocity

angular velocity

The rate at which angular displacement takes place

anteroposterior (AP) axis

The axis that passes horizontally from front to back, perpendicular to the frontal plane

Archimedes' Principle

Law governing buoyancy, which states that a body immersed in water is buoyed up by a force equal to the weight of the fluid displaced by the body


B backward tilt

Pelvic motion in which the posterior surface moves somewhat backward and downward

base of support

Any part of the body in contact with the supporting surface and the intervening area

Bernoulli's Principle

Law governing fluid forces, which states that when flow velocity is high, fluid pressure is low, and when flow velocity is low, fluid pressure is high

bilateral axis

The axis that passes horizontally from side to side, perpendicular to the sagittal plane


The study of the mechanics of biological systems

boundary layer

A layer of fluid that is immediately adjacent to the surface of an object


An upward force that acts to support a body immersed in water


C cardinal plane

A primary plane, one that passes through the center of gravity

center of buoyancy

That point in the body at which the upward force of buoyancy acts

center of gravity

The “balance point” of the body; the center of mass; the intersection of the three cardinal planes

centrifugal force

The “center-fleeing” force acting on an object undergoing circular motion; a reaction force to centripetal force

centripetal force

The “center-seeking” force constraining an object to a circular path

coefficient of elasticity

A number that represents the ability of a material to resist deformation and to return to its original state

coefficient of friction

A number that represents the resistance to rolling or sliding motion that exists between any two surfaces

coefficient of restitution

See coefficient of elasticity


Force ...

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