A merry-go-round of radius R,shown in the figure, is rotating at constant angula
ID: 2062582 • Letter: A
Question
A merry-go-round of radius R,shown in the figure, is rotating at constant angular speed. Thefriction in its bearings is so small that it can be ignored. Asandbag of mass mis dropped onto the merry-go-round, at a position designated byr.The sandbag does not slip or roll upon contact with themerry-go-round.Rank the following different combinations of m and ron the basis of the angular speed of the merry-go-round after thesandbag "sticks" to the merry-go-round.
m= 10kg
r = .25 R
m= 15kg
r = .75 R
m=20kg
r = .25R
m=10kg
r = .5R
m= 40kg
r= .25R
m=10kg
r= 1.0R
Explanation / Answer
conservation of angular momentum
I11=I22
I2 = I1 + mr^2
1)
mr^2 = 10/16
2)
mr^2 = 135/16
3)
mr^2 = 20/16
4)
mr^2 = 10/4 = 40/16
5)
mr^2 = 40/16
6)
mr^2 = 10 = 160/16
More mr^2 means more I2
More I2 means less 2
The order is
6 < 2 < 4 = 5 < 3 < 1 (or) 1 > 3 > 5 =4 > 2 > 6