Question

Three point charges are arranged along the x-axis. charge q1 = +3 µc is at the origin, and charge q2 = "5 µc is at x = 0.200 m. charge q3 = "8 µc. where is q3 located if the net force on q1 is 7.00 n in the -x-direction?

Answer 1

Force on charge q1 due to charge q2 is given as

`F = (kq_1q_2)/(r^2)`

`F = (9*10^9 * 3*10^(-6)*5 * 10^(-6))/(0.2^2)`

`F = 3.375 N`

Now the net force on q1 is 7 N so the force due to q3 must be

`F = 7 - 3.375 = 3.625 N`

`F = (kq_1q_3)/(r^2)`

`3.625 = (9*10^9 * 3*10^(-6)*8*10^(-6))/(r^2)`

by solving above

`r = 0.24 m`

so q3 is at distance 0.24 m from q1