Input (grade 13): The shear stress at a point within a shaft is: where: r is the distance from the center of rotation Note that the highest shear stress is at the point where the radius is maximum, the surface of the shaft.
Output (grade 12): The shear stress at a point on a shaft is: T is the applied torque, r is the distance from the center of rotation, and J is the polar moment of inertia.