A uniform disk with a mass of 900 g and radius 17.0 cm is rotating on frictionless bearings with an rotational speed of 18.0 Hz when Jill drops a 180-g clod of clay on a point 8.70 cm from the center of the disk, where it sticks. What is the new rotational speed of the disk?
According to the law of conservation of the angular momentum
I•ω1 = (I +Io) • ω2
M•R^2/2 • 2•π•n1 = (M•R^2/2 + mr^2) • 2•π•n2
n2= (M•R^2/2 • n1)/ (M•R^2/2 + mr^2) (Hz)
where M =0.9 kg, R=0.17 m, n1=18 Hz,
m =0.18 kg, r =0.087 m