A playground merry go round has a mass of 125kg and radius of 1.6m is rotating with a frequency of 0.42 rev/s. What is the magnitude of its angular velocity in radians per second after a 25kg child gets onto in be grabbing by its edge? The child is initially at rest.

Answer 1

angular momentum is conserved

initial ang. mom. of ride = final ang. mom. of ride + ang. mom. of child

Answer 2

where did mom came from

Answer 3

AngularMomentumInitial=AngularMomentumFinal+AngularMomentumChild

No Moms involved.

Answer 4

since L=Iw, I=aMR^2, and a for disk(merry go round) a=1/2 and hoop(how child is moving on the merry go round) a=1
0.42rev/s =2.638937829 rad/s

I've tried
1/2(125)(1.6^2)(2.638937829)=1(125+25)(1.6^2)w
w=1.099
but the answer came out wrong

Answer 5

The child is not a hoop. The child is a point mass. I= m r^2