고체역학 (Gere) — Torsion: Problem 3.7-3

3.7-3 A motor driving a solid circular steel shaft with diameter \( d = 38 \text{ mm} \) transmits \( 37 \text{ kW} \) to a gear at \( B \). The allowable shear stress in the steel is \( 40 \text{ MPa} \). Calculate the required speed of rotation (number of revolutions per minute) so that the shear stress in the shaft does not exceed the allowable limit.