Angular Kinetics Terms Flashcards
Angular impulse
Change in angular momentum equal to torque x time interval
Angular momentum
Quantity of angular motion possessed by body; moment of inertia x angular velocity (w)
Asymmetrical movement
Compensatory: keep body upright, kicking legs forward will cause body to rotate backwards, counter-rotation keeps body stationary
Initial: Swinging arm at shoulder joint will cause whole body to rotate forward
Conservation of Angular Momentum
In the absence of an external torque, every system remains in constant rotational state; when angular momentum conserved, there is trade off between moment of inertia/angular velocity
Local term
Examining the momentum of an individual segment of the system
Moment
Dealing with rotation
Moment arm
Perpendicular distance between the line of action of the force/axis of rotation
Moment of inertia
Product of mass times radius of gyration squared (kg m^2)
Principal moment of inertia
Inertia relative to one of the principal axes of the body (yaw, pitch, roll); low inertia in yaw/transverse, high inertia in roll/frontal
Radius of gyration
Distance from axis of rotation to point where body’s mass is concentrated
Remote term
Examining the momentum of the entire system
Torque
Force that produces rotation (moment of force); dependent on magnitude of force, point of application, direction
Linear equivalent of torque
Force
Linear equivalent of moment of inertia
Mass
Linear equivalent of angular momentum
Momentum
