FORGET k, 10^-6 etc etc which are the same for both
put -9 at x = 0
put + 16 at x = 1
from negative x a + 1 charge
pulled right to x= 0 but pushed left from x = +1
so left of 0, final x is negative
9/x^2 = 16/(1-x)^2
9 (x^2 - 2 x + 1 ) = 16 x^2
9 x^2 - 18 x + 9 = 16 x^2
7 x^2 + 18 x - 9 = 0
x = [ -18 +/-sqrt ( 324 + 252)]/14
use - answer to get spot
[ -18 - 24 ]/14
= -42/14
= -3
3 left of zero where the 9 charge is and 4 left of the 16 charge
===================
CHECK
3 left of -9
force right 9/9 = 1
4 left of + 16
force left 16/16= 1
whew
2 point charges -9nC n 16nC are separated by distance 1m find the position along the line joining the charges on which the resultant electric intensity is zero
1 answer
1 answer