00:01
Okay, so unfortunately with the numbers that we are given in the problem and arranging them in this way, the solution to this problem is not physically possible, and that's because a will only be pulling on b in the x direction, and c will be pulling on b in the y direction, and they will be pulling unequally.
00:26
Whereas any chart to be placed at q will provide an equal x and y force on b.
00:32
So it can't be large enough to balance a and balance c because we're going to need different forces to balance the x and the y directions.
00:43
And i'll prove that here in just a second.
00:46
Starting with the x directions.
00:48
The force from a and b, this is going to be an attractive force because it's negative and a positive.
00:54
And the force from d on b is going to be a positive force.
00:59
Or so this will have to be a repulsive force to balance out that one.
01:06
So it's force times the cosine of 45 degrees to get the x component of it.
01:11
Those two forces have to balance each other out.
01:14
So they have to be equal.
01:18
Plugging in our equation for the force from a to b, it's k, qa, qb over a squared where it's the side of r square.
01:26
And then doing the same thing for d and b.
01:30
This distance r, we can find just by taking the pythagorean theorem, if the side of the squared is a, then r squared is 2a squared.
01:40
So a squared plus b squared equals c squared.
01:44
And if the sides are the same, so it's a squared plus a squared, you get 2a squared equals r squared.
01:52
And so since down here we have r squared, we can just put 2a squared there.
01:58
Now this is equal to zero, so the bulsmore.
02:01
This one's constant will cancel.
02:03
We divide everything by that...