ltem 11 A 43-kg child stands on the edge of a 450-kg playground merry-go-round t
ID: 1782360 • Letter: L
Question
ltem 11 A 43-kg child stands on the edge of a 450-kg playground merry-go-round that is turning at the rate of 1 rev every 2.2 s. He then walks to the center of the platform. Part A If the radius of the platform is 1.5 m, what is its rotational speed once he arrives at the center? Assume that the platform is a uniform disk, and the child is "point-like", that is, his dimensions are so small compared to the platform size, that he can be considered to be a point-mass. are cnisdered to be a point-mass.his Hints wf = Submit My Answers Give Up ContinueExplanation / Answer
11.
A)
Ip = moment of inertia of the platform = (0.5) MR2 = (0.5) (450) (1.5)2 = 506.25 kgm2
wi = initial angular speed = 1x 3.14/2.2 = 1.43 rad/s
wf = final angular speed = ?
m = mass of the child = 43 kg
using conservation of angular momentum
(Ip + mR2) wi = Ip wf
(506.25 + (43) (1.5)2) = (506.25) wf
wf = 1.2 rad/s
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