A small child of mass 15 kg is sitting on the edge of a small playground merry-t
ID: 2239896 • Letter: A
Question
A small child of mass 15 kg is sitting on the edge of a small playground merry-to-round.
The merry-go-round is a disk of mass 100 kg and a radius of 2.5 meters. Suppose a larger
kid of mass 55 kg is running as fast as he can and jumps onto the edge of the merry-goround.
If he can run with a speed of 5.0 m/s what is the final angular velocity of the
merry-go-round?
What is the force the small child must exert on the hand hold in order to stay on the merry-goround
after it has attained this angular velocity?
Please show detailed steps
Explanation / Answer
from angular momentum conservation; m1*v*r = I*w => 55*5*2.5 = [(100*2.5^2/2) +(15*2.5^2) +(55*2.5^2)]*w => w = 0.917 rad/s force exerted by small child = m2*w^2*r => F = 15*0.917^2*2.5 = 31.53 N