Consider a cantilever beam with circular cross-section subjected to a concentrated torsional moment. An elementary Mechanics of Materials Theory analysis gives the stress field within the beam as Tij = 0 Mz My Mz 0 0 My 500 0 where M is the applied moment and I is the polar moment of inertia. Does this stress field satisfy equilibrium if body forces are neglected? What does this say about the assumptions made for the Mechanics of Material Theory?