[填空题]
A uniform disk turns atj4e9l4wevk w2 2.8j3xl4 -ac*hhj fjz*t4 $rev/s$ around a frictionless spindle. A nonrotating rod, of the same mass as the disk and length equal to the disk’s diameter, is dropped onto the freely spinning disk, Fig. 8–49. They then both turn around the spindle with their centers superposed. What is the angular frequency in rev/s of the combination? $rev/s$