고체역학 (Beer) — Principal Stresses Under a Given Loading: Problem 8.26

8.26 Solve Prob. 8.25, assuming that the motor rotates at 360 rpm. (Reference Prob. 8.25: The solid shafts \(ABC\) and \(DEF\) and the gears shown are used to transmit 20 hp from the motor \(M\) to a machine tool connected to shaft \(DEF\). Knowing that the motor rotates at 240 rpm and that \(\tau_{\text{all}} = 7.5 \text{ ksi}\), determine the smallest permissible diameter of (a) shaft \(ABC\), (b) shaft \(DEF\).)