Avariable-speed belt drive consists of the two pulleys, each of which is constructed of two cones which turn as a unit but are capable of being drawn together or separated so as to change the effective radius of the pulley. if the angular velocity of pulley 1 is 3.5 rad/s (constant), determine the angular acceleration α2 = ω˙2 of pulley 2 in terms of the rates of change r˙1 = 6 mm/s and r˙2 = 8 mm/s. the instantaneous effective radii are r1 = 85 mm and r2 = 60 mm.