Answer:
(B) Vertically upward
Step-by-step explanation:
r = Side of triangle = 14 cm
q = Charge = -2.5 nC
Electrical force is given by
![F=(kq_1q_2)/(r^2)\\\Rightarrow F=(8.99* 10^9* (2.5* 10^(-9))^2)/(0.14^2)\\\Rightarrow F=2.86671* 10^(-6)\ N](https://img.qammunity.org/2021/formulas/physics/college/lzm0dquxd3gm8myp39c3e67x0u5ss3phfg.png)
For the top charge
Net force on both charges is given by
![F_n=2Fcos\theta\\\Rightarrow F_n=2* 2.86671* 10^(-6)* cos30\\\Rightarrow F_n=4.96529* 10^(-6)\ N](https://img.qammunity.org/2021/formulas/physics/college/db8zb9t65ogliywj3xr6xvctazmal7kdwm.png)
The net force acting on the top charge is
![4.96529* 10^(-6)\ N](https://img.qammunity.org/2021/formulas/physics/college/l70arck1c131p2fealx8v1u0xn4ub39hpx.png)
Here the forces are symmetrical hence, the net force is along +y axis i.e., upward