While the exact distribution of the shearing stresses in a hollow cylindrical shaft is as shown in Fig. a, an approximate value can be obtained for Tmax by assuming that the stresses are uniformly distributed over the area A of the cross section, as shown in Fig. b, and then further assuming that all of the elementary shearing forces act at a distance from O equal to the mean radius 1(c + c) of the cross section. This approximate value is To = T/Arm, where Tis the applied torque. Determine the ratio Tmax / To of the true value of the maximum shearing stress and its approximate value To when c/c2 = 0.9. Treas (a) The ratio Tmax /TO is TO AMA (b)