Question

Three point charges are located it the positive x-axis of a coordinate system. Positive point charge 𝒒𝟏 = 5 𝑛𝐶 and negative point charge 𝒒𝟐 = −10 𝑛𝐶, are located 3 cm and 5 cm from the origin respectively. Determine the total force of another point charge 𝑸 = −𝟏 𝝁𝑪 at the origin due to the other two chargers.

Answer 1

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

$F_{1Q}=\frac{9×10^9×5×10^{-9}×1×10^{-6}}{(3×10^{-2})^2}\\=5×10^{-2}N$

$F_{2Q}=\frac{9×10^9×10×10^{-9}×1×10^{-6}}{(5×10^{-2})^2}$

$=3.6×10^{-2}N$

Total Force$=-3.6×10^{-2}+5×10^{-2}$

$=1.4×10^{-2}N$