How Do You Calculate Angular Distance and Displacement in Biomechanics?

[nsxviper]

Homework Statement

A tennis player takes 3 preparatory swings, each swing travels through an arc of 140 degrees each way. At the 4th swing, the ball is struck and the swing travels 240 degrees. Calculate the total angular distance and angular displacement of the club.

Homework Equations

I have no clue, is it theta = d/r ?

The Attempt at a Solution

I am so confused because all I am given is the arc and no radius. Is the angular distance in rads or meters? I can't seem to find the formula for this. I've taken physics and I know how to solve for angular velocity and angular acceleration but never did solve for angular distance. This is for my biomechanics class.

 

[tiny-tim]

Welcome to PF!

Hi nsxviper! Welcome to PF!

… I've taken physics and I know how to solve for angular velocity and angular acceleration but never did solve for angular distance.

Since you obviously understand the difference between angular velocity and ordinary velocity, and between angular acceleration and ordinary acceleration, just go with the flow … the difference between angular distance and ordinary distance is exactly the same.

a (tangential) = rα

v (tangential) = rω

s (tangential) = rθ

(and so, for example, if you've done the standard constant acceleration equations, v = u + at etc, you can apply them to constant angular acceleration, just substituting α for a, ω for v, and θ for s)