Angular Kinematics Flashcards
Angular Motion
Motion about an axis of rotation
Axis of Rotation
Imaginary line perpendicular to the plane of rotation passing through
Joint Angle
Angle between anatomical position (0 degrees) and the position of the body segment that has moved
Relative Angle
Joint angle between 2 adjacent segments.
Absolute Angle
Angle between a body segment and either horizontal or vertical
Goniometer
Hand-operated tool used for measuring the angle present at a joint
Range of Motion
The angle through which a joint moves from anatomical position to the extreme limit of segment motion in a particular direction (angular displacement)
Angular Distance
- Scalar quantity
- Total angular change
- Units: deg, º, rad, rev
Angular Displacement
- Vector quantity
- Change in angular position.
- Formula: θ = angle2 - angle1
Radian
- Unit of angular measure used in angular-linear kinematic quantity conversions
- 57.3 degree
Angular Speed
- σ (sigma)
- Scalar quantity.
- angular distance/change in time.
- σ = φ/t
- φ = angular distance
Angular Velocity
- Rate of change in angular position
- Change in angular position/change in time
- ω (omega)
- ω = θ/t
- ω = θ2 - θ1/t2 - t1
Angular Acceleration
- Rate of change in angular velocity
- α (alpha)
- Change in angular velocity/change in time
- The angular acceleration may be positive, negative, or zero (deg/s², rad/s²).
- α = (ω2 - ω1) / (t2 - t1)
- α = Δω / Δt
Right Hand Rule
- Procedure for identifying the direction of an angular motion vector
- Fingers of the right hand are curled in the direction of an angular motion
- Thumb points in the direction of the resultant vector
Angular and Linear Distance Conversion
- l = rφ
- l is linear distance
- r is radius of rotation
- φ (phi) is angular distance
Angular and Linear Displacement Conversion
- d = rθ
- d is linear displacement
- r is radius of rotation
- θ is angular displacement
Angular and Linear Speed Conversion
- s = rσ
- s is linear speed
- r is radius of rotation
- σ (sigma) is angular speed
Angular and Linear Velocity Conversion
- v = rω
- v is linear velocity
- r is radius of rotation
- ω (omega) is angular velocity
Angular and Linear Acceleration
Angular acceleration may be resolved into 2 perpendicular linear acceleration components:
- Tangential acceleration
- Radial acceleration
Tangential Acceleration
- Component of acceleration of a body in angular motion directed along a tangent to the path of motion
- Represents change in linear speed
- at = rα
Radial Acceleration
- Component of acceleration of a body in angular motion directed toward the center of curvature
- Represents change in direction
- ar = v^2/r
