1. Prologue
This PowerPoint will be proceeded by a derivation of important Mohr Circle equations.

2. Note this txy turns the element CCW, plot x below the s axis

3. Recall this txy turns the element CCW, plot x below the s axis

6. Worked Example 2

9. sp1 = C + R

12. Yellow angle has tangent
20/50, yellow angle = 21.8o

14. o = 158.2o

17. An example from New Zealand
In New Zealand the shear stress t sign convention is reversed from the one we are currently using. Doesn’t matter, circles are symmetrical.
Notice the strong graphical use, relying on a scale (ruler) for graphing and measurements.
Video by Steve Tomsett at CPIT