0:00
So we have this situation.
00:01
It's a statics problem.
00:03
We've got an unknown force p applied down here.
00:08
There's friction on both surfaces.
00:11
We're given that the angle of friction is 15 degrees.
00:16
So we know the coefficient of static friction is the tangent of that, which is 0 .268.
00:24
Okay.
00:25
Now, so let's draw free body diagrams.
00:32
So let's start with a.
00:34
So fl is the force in the link, which we know goes parallel to the link.
00:49
There's the frictional force.
00:51
I'm not sure about the direction of that.
00:54
The sign of it when we're done will tell us something about it.
01:06
Here's our equations of motion.
01:08
There is no acceleration.
01:09
It's a statics problem.
01:16
And then our friction looks like this.
01:21
So we understand that that's an absolute value on the friction.
01:24
Since i, like i said, we don't know exactly what the sign of the friction up here is.
01:37
So here's block two, block b, and i left out the normal force.
02:02
We know it's got to be there...