00:01
So here we know that we're going to apply the conservation of angular momentum.
00:06
The angular momentum initial will be equal to the angular momentum final.
00:10
And we can say that the moment of inertia times the initial angular velocity would be equal to the moment of inertia prime.
00:20
So essentially final multiplied by the final angular velocity.
00:25
And so the initial moment of inertia would be equaling mr squared divided by two.
00:31
So essentially this would be the moment of inertia of the merry ground itself modeled as a disk plus this would be the mass of child a times r squared plus the mass of child b times r squared plus the mass of child c times r squared.
00:53
And so we can solve this would be equaling essentially m over two so 100 kilograms over two multiple or rather plus plus.
01:08
The mass of the first child 22 kilograms plus the second child 28 kilograms plus the third child 33 kilograms all multiplied by the radius squared so 1 .6 meters quantity squared and this is equaling 340 .48 kilograms meters squared the final moment of inertia would be equal to the exact same thing.
01:38
However, now child b moves to the center of the merry -go -round.
01:45
So the center of the now child b is not contributing any, the mass of child b is not contributing to the moment of inertia final.
01:55
And so we can say that this would be 100 kilograms over 2 plus 22 kilograms...