00:01
First thing to recognize is that if you put a positive test particle there, you know, the q2, by the way, q2 is negative, right? so q2 is gonna attract this and q1 is gonna repel.
00:19
But because of the distances, there is no way electric field is zero here, you know, the electric field is kq over r squared.
00:31
And there's no way it's here, zero here, because they attract each other.
00:35
So it has to be here somewhere, okay, on the left hand side.
00:40
That's first thing to recognize.
00:41
So if you put a positive charge there, so q1 is gonna repel and q2 is gonna attract and there is a way they can balance each other.
00:53
So let's write that out.
00:56
So f1 will be equal to f2 at that x point.
01:03
So f1 is k 1 .4 times 10 to the negative 8.
01:10
By the way, the picture shows negative 8 and your writing shows negative 5.
01:14
So i went with negative 8 from the picture, x squared, and then k times 1 .8 times 10 to negative 8.
01:25
It's not gonna matter here because this is gonna go away, but i took that for the entire problem.
01:36
So technically we have a quadratic equation here, okay, like this.
01:52
And then bring everything to one side, make this positive, so you will have 0 .544 x minus 0 .0436 equal to 0.
02:09
So this one produces two answers, okay.
02:12
The first one is negative 0 .08, the other one is 1 .34.
02:20
These are all meters.
02:22
Now this can't happen because that means that you're somewhere here, and we already decided it's not there.
02:27
So this is your answer, okay.
02:30
That's where the e is 0.
02:33
On the, if you want, like on the negative side, so left hand side, or you can call x equals negative 1 .3 meters.
02:41
According to the origin, actually, you should write that, because according to the origin, it's negative.
02:47
Now for the b part, now we have q3 here.
02:53
So q1, q3, they're gonna repel each other because they are both positive.
02:59
And q2, q3, they're gonna attract each other, okay...