00:01
In this case we have three charges arranged on a line.
00:03
We're told that they're 20 centimeters between these, between q1 and q3, and then q2 is halfway between them.
00:12
And then we automatically convert into meters because all electricity and magnetism problems have to be done with meters and not centimeters.
00:23
So we automatically convert to meters from the word go.
00:26
So our charges are given in microcoulombs, which are 10 to the minus 6 coulombs.
00:34
And we then want to find the magnitude of the attractive force on either outside ball due to only the middle one.
00:47
So for part a, we want to find the magnitude of f.
00:53
So it's going to be kq1q2, and it's going to be the absolute value of that divided by, i'll say, d squared.
01:05
D is my 0 .1 meters.
01:08
We know k is 9 times 10 to the 9th newton meters squared per coulomb squared.
01:18
So this comes out to be, it's 9 times 10 to the 9th, because we don't care about signs, we're only interested in magnitude.
01:32
It's 1 .66 times 10 to the minus 6 quantity squared.
01:39
And then our distance was 0 .1 squared.
01:44
And then my answer will be in newtons.
01:46
And that comes out to be 24 .8 newtons...