00:02
Okay, this is an interesting problem.
00:05
We are given two magnetic fields that are perpendicular to each other.
00:09
So let's start.
00:10
We know that this is going to be a three -dimensional problem.
00:14
So let's draw three -dimensional axis here.
00:16
So we have our z axis.
00:18
We have our x -axis.
00:20
We have our y -axis.
00:22
So now we have negative z in this direction.
00:26
We have negative x in this direction, and then our negative y goes this way.
00:34
So now we have two magnetic forces, our magnetic fields.
00:40
Let's do those in green.
00:41
Magnetic field.
00:43
We have one flowing into the earth.
00:48
Now, for simplicity, let's call the, this will be x.
00:53
Let's call the x, y plane.
00:56
So the plane created by these two, this will be our earth.
01:06
And z will be into and or out of the earth.
01:10
So we have one component of the magnetic field flowing into the earth or in the negative z direction, and then we have another portion of the magnetic field flowing in the negative x direction, which is parallel to the earth, flowing this way.
01:28
Okay, so we have that.
01:32
Let's draw, i'm going to take this xy plane and move it over here, just so we can play around with it and see, have a better description of what we're doing.
01:53
Drawing in three dimensions is always fun.
01:56
So there's our plane.
01:58
We are told we have a wire that flows straight down into the earth.
02:05
That's the direction of flow.
02:07
We don't care where it's going or where it came from.
02:10
We only care about this specific length of layer, we are given.
02:15
We hold it has a charge flow.
02:18
So we're told the length and we know the current flowing in the wire.
02:23
And current is typically represented by the letter i, capital i.
02:29
And we are also given both of these two magnetic fields.
02:33
I'm going to call this b sub z, the b direction, and this one, b sub y, or not it's b sub x for the x direction.
02:43
B sub x direction.
02:48
V sub x.
02:50
Okay, so now what equation are we going to use? we have a perfect equation that represents all of the factors that we're given here.
03:02
The force, which is what we're trying to find here, we want the magnitude and the direction of the force.
03:09
So we're going to want to keep our directions in mind while we're calculating this, which means we're probably going to have to use the right -hand rule.
03:16
So we have the force is equal to the current.
03:22
Now this equation relates magnetic field to current or a flowing charge.
03:28
So it's the current times the length times the magnetic field.
03:34
Now the important factor here is that it's sine of theta of all of that, all of that multiplied by sine of theta.
03:42
Which, what does that mean exactly? so typically when you have a sign in your equation, it's taking into consideration only the portion of this segment that relates to this segment in the perpendicular fashion.
04:04
So the current flowing only perpendicular to be will be considered here...