00:01
What is their current? so as we can see from our figure, both wires have current going the opposite direction.
00:10
So our magnetic force between two current carrying wires is mu not i1, i2 times l divided by 2 pi times r.
00:21
Since our currents are equal, that's just equal to mu not i squared l over 2 pi r.
00:28
And in our vertical direction, our fy is equal to t cosine theta, which is equal to mg.
00:36
So our tension is mg divided by cosine theta.
00:41
In our x direction, we get t sine theta.
00:45
Here, our net fb is zero, and our force in the x direction is equal to fb.
00:53
So we can set a mu not i squared l over 2 pi r.
00:59
Equal to m g over cosine theta times sine theta.
01:05
So i is equal to the square root of 2 pi r sine theta times m over l g divided by mu not cosine theta...