Question

Dos cargas puntuales se localizan en el eje +X de un sistema de coordenadas. La carga q1= 1nC esta a 2cm del origen y la carga q2= -3 nC esta a 4cm del origen. ¿cual es la fuerza tras que ejercen estas dos cargas sobre una carga q3= 5nC que se encuentra en el origen?

Answer 1

Answer:

F_net = 1.125 10⁻⁶ N

positive direction of the x axis

Explanation:

The electric force is given by Coulomb's law

           F =$k \frac{q_1q_2}{r_{12}^2}$

also used  charge of equal sign repel each other.

We appease this information to our problems

the charge q₁ is positive and the charge q₃ is positive for which the force is repulsive; ; a charge q₂ is negative so the force is attractive.

If we apply that the forces are vectors

            F_net = - F₁₃ + F₂₃

           F_net = $-k \frac{q_1q_3}{r_{13}^2} + k \frac{q_2q_3}{r_{23}^2}$

            F_net = k q₃ ( $- \frac{q_1}{r_{13}^2} + \frac{q_2}{r_{23}^2}$ )

let's look for the distances

          r₁₃ = 2-0 = 2 cm = 2 10⁻² m

          r₂₃ = 4-0 = 4 cm = 4 10⁻² m

let's substitute

            F_net = 9 10⁹ 5 10⁻⁹ ( $- \frac{1 \ 10^{-9}}{2 \ 10^{-2}} + \frac{3 \ 10^{-9}}{4 \ 10^{-2}}$)

            F_net = 45 (- 0.5 10⁻⁷ + 0.75 10⁻⁷)

            F_net = 1.125 10⁻⁶ N

the positive sign indicates that the outside has a positive direction of the x axis, that is, it is to the right