Posted by Kristi on Tuesday, August 16, 2011 at 12:35pm.
A solid disk rotates in the horizontal plane at an angular velocity of 0.034 rad/s with respect to an axis perpendicular to the disk at its center. The moment of inertia of the disk is 0.11 kg·m2. From above, sand is dropped straight down onto this rotating disk, so that a thin uniform ring of sand is formed at a distance 0.38 m from the axis. The sand in the ring has a mass of 0.39 kg. After all the sand is in place, what is the angular velocity of the disk?

Physics  bobpursley, Tuesday, August 16, 2011 at 12:43pm
Assume conservation of angular momentum
Iinitial*wi=(I' wf)
where I'=initial I + masssand*r^2