00:01
Okay, so here we have a man and initiates his arms down by sides.
00:06
He's spinning on a light friction table and then he extends his arms as shown here.
00:11
His angular momentum is going to remain the same, but what is going to change? so i'm going to use a few equations here.
00:18
We have inertia is equal to angular momentum over angular velocity.
00:25
So we can say that i equals inertia.
00:31
L equals angular.
00:33
Momentum and omega equals angular velocity so as he extends his arms he's going to slow down so angular velocity is going to decrease this means that his inertia is going to increase however we don't get given the option for increase in in inertia in rotational inertia so that can't be one of the options it's not it's not one of the options provided to us so if we then look at the equation for rotational kinetic energy.
01:09
We have e is equal to half i omega squared.
01:16
And we know that i is equal to l over omega so we can substitute that in.
01:19
We know that's what we can say that the e is equal to a half l over omega multiplied by omega squared.
01:28
Okay, i is l over omega...