A playground merry-go-round has a disk-shaped platform that rotates with negligible friction about a vertical axis. The disk has a mass of 240 kg and a radius of 1.4 m. A 33- kg child rides at the center of the merry-go-round while a playmate sets it turning at 0.20rpm. If the child then walks along a radius to the outer edge of the disk, how fast will the disk be turning? (answer must be in rpm)

3 answers

http://www.jiskha.com/display.cgi?id=1258578369
i tried the technique that was posted on there, but the answer was wrong. and my answer is supposed to be in RPM.
can somebody explain how to do this problem without changing it to radians? the final answer has to be in rates per minute