a uniform disk turns at $3\mathrm{.}3$ rev$/$s around a frictionless central axis. a nonrotating rod, of the same mass as the disk and length equal to the disks diameter, is dropped onto the freely spinning disk. they then run together around the axis with their centers superposded. how many times the mass of the disk would the rod need to have to make the disk slow to $0\mathrm{.}2$ rev$/$s