16-134. Determince Prob. 16-133 the angular acceleration of the plate CD of the stone-crushing mechanism at the instant AB is horizontal. At this instant 0-30 and -90. Driving link AB is turning with constant angular velocity of wAB = 4 rad/s. A D 4 ft <<-=90° 0-30° B WAB = 4 rad/s A 3 ft Prob. 16-134 2 ft-