Torsional shear strain varies linearly across a homogeneous cross section.

Torsional shear strain is a maximum at the outermost radius for a homogeneous and a nonhomogeneous cross section.

Torsional shear stress is a maximum at the outermost radius for a homogeneous and a nonhomogeneous cross section.

The formula can be used to find the shear stress on a cross section of a tapered shaft.

The formula can be used to find the relative rotation of a segment of a tapered shaft.

The formula can be used to find the shear stress on a cross section of a shaft subjected to distributed torques.

The formula can be used to find the relative rotation of a segment of a shaft subjected to distributed torques.

The equation cannot be used for nonlinear materials.

The equation can be used for a nonhomogeneous cross section.

Internal torques jump by the value of the concentrated external torque at a section.