Definitions
Ch 6
Ch 6
Curvilinear Motion
The motion of an object that follows a curved path.
Equilibrium
The condition of a system when neither its state of motion nor its internal energy state tends to change with time.
A state of harmony between opposing forces or actions.
Angular (Rotational) Motion
The motion of an object around a fixed point or axis.
Motion that is circular or rotary. Somersaulting, twisting, rolling, swinging, rocking, spiraling, and pirouetting are all forms of angular motion.
Balance
Ability of an athlete to control their movements for a particular purpose.
We can use the term balance to refer to the ability to control the forces that make an athlete stable.
Angular Speed
(rad/s) Describes the rate of spin/rotation of an athlete or object. Change in theta divided by change in time (scalar - magnitude only).
Stability
Resistance to the disturbance of balance.
The mechanical definition of stability specifically relates to how much resistance the human can put up.
Angular Velocity
(rad/s) Describes the rate of spin/rotation of an athlete or object. Change in theta divided by change in time; takes into account the direction of motion (vector - magnitude and direction).
Linear Stability
Concerns an athlete who is moving in a particular (curvi)linear direction.
Resistance against being stopped or having their direction changed once on the move.
Angular Acceleration
(rad/s²) The rate of change of an object’s angular velocity/speed with respect to a change in time (vector - magnitude and direction).
Rotary Stability
Concerns an athlete who is rotating.
Resistance against being tilted, tipped over upended, or spun around in a circle.
Centripetal Force
Required when changing straight line motion into circular motion.
Any rotating object has a force that acts toward its axis of rotation. This inward force is called a centripetal force.
Static
The mechanical term to describe human movement that is in a constant state of motion (or no motion).
Centrifugal Force
The desire of an object to continue in a straight line; centrifugal means pulling outward from the axis of rotation.
When objects or athletes are made to rotate, their inertia constantly tries to make them travel in a straight line. The pull of inertia competes against the inward pull of centripetal force. A common name for the pull of inertia in this situation is centrifugal force. Centrifugal force is really inertia in disguise.
Dynamic
A term to describe motion that is under-going change, that is varying.