Biomechanics-angular Motion Flashcards
Angular motion
When a body moves in a circle or part of a circle about an axis of rotation
Axis of rotation
Straight line through all points of rotating rigid body around which all other points of the body move in circles
What are the 3 axes of rotations?
1) longitudinal
2) frontal
3) transverse
What is the longitudinal axis?
From head to foot of the body. Causes a twisting action in diving, gymnastics and figure skating
What is the frontal axis?
From front of the body to the back. Rotation causes a cartwheel motion
What is the transverse axis?
From the left to the right of the body. Causes a somersault action.
How is angular motion created?
Created by an eccentric force which passes outside the center of mass
Moment of inertia
Tendency to resist angular acceleration
Tendency to resist a change of state in motion or rotation
Angular velocity
Rate of spin in a particular direction or angular displacement per unit of time
Angular momentum
Amount of motion of a rotation a body
How to calculate moment of inertia
Sum of the mass x the distance of the mass from the axis of rotation squared
Angular velocity
= angular displacement divided by time
How to calculate Angular momentum
Angular momentum = moment of inertia x angular velocity
Moment of inertia
The reluctance of a body to change its state of angular motion or rotation
What affects moment of inertia
Mass - the greater the mass, the larger the moment of inertia
Distribution of mass- the closer the mass of the body to the axis of rotation , the smaller the amount of inertia
