An endurance strength test machine consist of a motor, a gearbox, two elastic shafts, bearings, and the test gears. The gear forces are created by twisting the shafts when the gears are mounted.
At one location the shafts were twisted at an angle representing one gear tooth. Find the gear force in the test gears as a function of the parameters given in the sketch.
The angle the shaft ends are twisted is one gear tooth, or
This twist is spread evenly between the two shafts giving each a twist of
Gives the twist angle as