OK, one more and I think I will have it for this HW set.

A charge of 1.82E-9 C is placed at the origin, and a charge of 4.32E-9 C is placed at x = 1.26 m. Find the position at which a third charge of 3.05E-9 C can be placed so that the net electrostatic force on it is zero.
Thanks for all of your help!!

Question

OK, one more and I think I will have it for this HW set.

A charge of 1.82E-9 C is placed at the origin, and a charge of 4.32E-9 C is placed at x = 1.26 m. Find the position at which a third charge of 3.05E-9 C can be placed so that the net electrostatic force on it is zero.
Thanks for all of your help!!

anonymous · Answer

$$F = k_e {q_1 q_2 \over r^2}$$The third charge must be placed such that$$F_{1/3} = F_{2/3}$$We know $k_e$, we know the charges, we can find the radius.