A 750g, 50-cm-long metal rod is free to rotate about a frictionless axle at one end. While at rest, the rod is given a short but sharp 1000N hammer blow at the CENTER of the rod, aimed in a direction that causes the rod to rotate on the axle. The blow lasts a mere 2.0ms. What is the rod's angular velocity immediately after the blow? The book gives the answer 8.0rad/s.