Podiatry

Angular Kinematics

Describing angular motion or displacement?

Angular Distance and Displacement:

Units of measurement: radians (1 rad=57,3 degrees), degree, revolutions (revs)

Angular Velocity ( w ) - Time rate of change of angular displacement (rad/s, deg/s, rev/s)
Linear velocity = change in displacement over time.
Angular velocity = change in angle over time.

Angular Acceleration:

Linear acceleration = a = change in velocity over time.
Angular equivalent = a = change in angular velocity over time.
Linear Velocity Endpoint (Implement) = Angular Velocity (w) x Radius of Rotation (r)
* Must only work in radians.

Object's COM which has a linear velocity it must be added to the equation.
Vball = V shoulder + (W x r)

Lecture Outcomes:
- Vball = Vankle + (W (angular velocity) x r (radius of rotation))
Real World Problem:
A Softballer rotates the bat horizontally at 10rad/s. If her shoulder is moving forward at 2m/s and the distance of the point of impact with the ball and her shoulder is 1m, what is the forward velocity of the end of the bat at the point of impact?

Equation that needs to be used:
Vball = Vshoulder + (W x r)
Vball = 2 + (10 x 1)
- Vshoulder = expressed in linear velocity (m/s)
- W = is angular velocity
- r = the shoulder radius of rotation

* Vball = 12m/s