00:02
Here, we have two pulleys connected together.
00:05
We know that point a on the smaller pulley, the 4 -inch pulley, is moving up at a velocity of 3 feet per second, or 36 inches per second.
00:17
We want to find the velocities of the center of the pulleys and a point b on the larger pulley.
00:25
So first, we can calculate the velocity of point o here.
00:32
The velocity of 0 will just be due to some of the radii involved here.
00:48
So this will be the radius of the larger one.
00:53
So b divided by the radius of the smaller one plus the radius of the bigger one, times that velocity of a, which would give us then that's an 8 over 12.
01:12
Times 36.
01:16
So that should give us 24 inches per second.
01:21
So fairly simple.
01:25
Then we want to calculate the angular velocity of the larger pulley.
01:33
The angular velocity of the larger pulley will just be the velocity of that center of rotation or the center of the polies divided by the radius of that larger pulley.
01:52
So that's 24 inches per second divided by eight.
01:56
In other words, that's three radians per second...