Question

Draw the net electric force on a +1-C charge placed at the center of:

a. A line segment of length 1.0 m with a +1-C charge and a –1-C charge at its endpoints;

Calculate the magnitude and determine the direction of the net electric force on the +1-

C charge placed at the center of configurations in a, b, and c.

Answer 1

Explanations & Calculations

• Both the charges at the ends of the line segment create the same electric force on the middle +1C charge.
• One is repulsive & the other is attractive.
• Therefore, both the forces act in the same direction as shown in the sketch.
• The magnitude is simply the addition of the two & the magnitude of each can be found with the help of Coulomb's equation.
• Then,

$\qquad\qquad \begin{aligned} \small \vec{F_{total}}&=\small 2\vec{F}\\ &=\small 2\bigg[\frac{kq_1q_2 }{r^2}\bigg]\\ &=\small 2\bigg[\frac{8.99\times10^9Nm^2C^{-2}\times1C\times1C}{(0.5m)^2}\bigg]\\ &=\small \bold{7.19\times10^{10}\,N} \end{aligned}$