Answer to Question #314330 in Electricity and Magnetism for Leo

Question

1.  A charge of Q₁ of 2 x 10^-6 C is placed on a line between two charges Q₂ of 1 x 10^-6 C and Q₃ of -6 x 10^-6 C. Q₁ is 10 x 10^-4 m from Q₂ and 20 x 10^-4 m from Q₃. What is the net force on Q₁?

Answer 1

Force

$F_3=\frac{kq_1q_3}{r^2}$

$$F_3=-\frac{9\times10^{9}\times2\times10^{-6}\times6\times10^{-6}}{(2\times10^{-3})^2}=-27000N$$

$F_2=\frac{kq_1q_2}{r^2}$

$$F_1=-\frac{9\times10^{9}\times2\times10^{-6}\times1\times10^{-6}}{(1\times10^{-3})^2}=18000N$$

$F_{net}=F_1+F_2$

$F_{net}=18000-27000=-9000N$