00:01
Okay, we have a situation that looks like this.
00:03
We're pulling straight down on a rope that goes around a frictionless pulley.
00:08
The radius of the pulley is half a foot, but we don't actually need that.
00:14
The rope is attached at the wall at point c.
00:21
There's a 30 -degree angle between the vertical and the rope on this side of the pulley.
00:29
So here's a free body diagram for the pulley.
00:32
I've drawn in the force of support because that's one thing we want.
00:37
We want to find the force at c and the force of support.
00:45
So we get three equations out of this in the x and y direction.
00:52
And also there's a torque equation, although the pulley is frictionless.
01:00
So there's not actually any torque on it because the rope just slides across.
01:12
I'm still going to write it as r times t1 minus t2.
01:15
That's not really applied to the pulley, though...