Week 2 Flashcards
Angular motion
When all parts of the body/object move through the same angle, in the same direction at the same time
Kinematics variables for an angle
Degrees, radians, revolutions
The equation for Pi (π)
Circumference / Diameter
How to convert degrees to radians
(degree) x (180/Pi)
e. g. 1 degree is 1 x (180/Pi)
= 0.01745329251
e.g. 180 degree is 180 x (180/Pi)
= 3.14159265359
Absolute angle
An absolute angle, also called a segment angle, is the angle of a segment relative to the perfect horizontal.
It is calculated by drawing a horizontal line at the distal end of the segment and measuring the angle from the right horizontal to the segment in a counter-clockwise direction.
Relative angle
The angle at a joint formed between the longitudinal axes of the body segments adjacent to the joint. Relative angles are always measured on the same side of a particular joint. A straight, fully extended joint is regarded as having a relative angle of 0°.
What angle would any joint be in the anatomical position
Zero
Degrees of freedom definition and how many
Movement of a joint in a plane
Three planes therefore, 3 degrees of freedom
How many degrees of freedom does the wrist have and what are they
3 degrees - flexion/extension, radioulnar deviation, rotation
How many degrees of freedom does the shoulder have and what are they
3 degrees - because it is a ball and socket joint it can move in any direction
How many degrees of freedom does the elbow have and what are they
2 degrees - flexion/extension and forearm pronation and supination
Angular displacement (θ)
Vector - Change in the angular position of an object or segment from start to finish
Right-hand thumb rule
Anticlockwise (positive)
Clockwise (negative)
Angular velocity equation (𝜔)
𝜔 = ∆ 𝜃 / ∆ t
𝜃 = angular displacement (°/s or rad)
t = time (s)
∆ = change
If someone is swinging on a high beam and we want to calculate the angular velocity of 50° with ti being 3.4s and tf being 3.9s
50° / (3.9 - 3.4)
= 50 / 0.5
100°/s
