Astepped shaft abc consisting of two solid circular segments is subjected to torques t1 = 20,000 lb-in and t2 = 8,000 lb-in acting in opposite directions. the larger diameter of the shaft is d1 = 2.25 in, and the smaller diameter is d2 = 1.75 in. if the radius of curvature at the transition between the larger and smaller diameters is a quarter circle, calculate the maximum shear stress τmax in the shaft.

During the apollo moon missions, astronauts were concerned about the effects of newton's third law of motion when: o a. they ejected waste water, because they were concerned that it would push them off course. o b. they reentered earth's atmosphere, because they were carrying heavy moon rocks. o c. they took off from earth, because a large force was required to generate large acceleration. o d. they detected incoming space debris, because the inertia of the debris could damage their ship.