Two point charges Q1 = 10µc and Q2 = 2µc are arranged along the x-axis at

x = 0 and x=4m respectively. Find the position along the x-axis where v = 0.

1 answer

field strength is proportional to the charge
... and inversely proportional to the square of the distance

d is the distance from the origin along the x-axis

10 / d^2 = 2 / (4 - d)^2

10 (4 - d^2) = 2 d^2

40 = 12 d^2