A merry-go-round of radius R. shown in the figure, is rotating at constant speed. The friction in its bearing is so small that it can be ignored. A sandbag of mass m is dropped onto the merry-go-round, at a position designated by r. The sandbag does not slip or roll upon contact with the merry-go-round.

Rank the following different combination of m and r on the basis of the angular speed of the merry-go-round after the sandbag "stick" to the merry-go-round.

(a) m=10kg, r=1.0R
(b) m=20kg, r=0.25R
(c) m=40kg, r=0.25R
(d) m=10kg, r=0.5R
(e) m=15kg, r=0.75R
(f) m=10kg, r=0.25R

From law of conservation of angular momentum,


Thus, more  means more , and more   means less .
The order is, (f)>(b)>(c)=(d)>(e)>(a)