A frictionless turntable is a uniform solid disk of mass 5.0kg and radius 0.50m. It spins freely about its central axis at 3.0rad/s. Two 1.0kg blocks initially rest on the edge of the disk at the same radius. The blocks are then pulled inward along radial grooves until they reach a radius of 0.20m. What is the angular speed of the system after the blocks have moved inward?
a) 7.5rad/s
b) 5.1rad/s
c) 4.8rad/s
d) 3.8rad/s