a 1.9 kgkg , 20-cmcm-diameter turntable rotates at 90 rpmrpm on frictionless bearings. two 510 gg blocks fall from above, hit the turntable simultaneously at opposite ends of a diameter, and stick. part a what is the turntable's angular velocity, in rpmrpm , just after this event? express your answer to two significant figures and include the appropriate units.