The four 11-Ib spheres are rigidly attached to the crossbar frame having a negligible weight. A couple moment M = (0.5t + 0.8) lb middot ft, where t is in seconds, is applied as shown. (Figure 1) Determine the speed of each of the spheres in 5 seconds starting from rest. Neglect the size of the spheres. Express your answer to three significant figures and include the appropriate units. Solution Torque T = mr 2 (o.5t+0.8) = 4*11/32*0.6 2 or = 2.02( (o.5t+0.8) =1.01 t+ 1.616 w= *t = (1.01 t+ 1.616 )*t = 1.01t 2 + 1.616 t v= r*w v= 5 0 (r*w)dt = 5 0 0.6(1.01t 2 + 1.616 t)dt = 5 0 (0.606t 2 + 0.9696t)dt =37.37 ft/sec .