Three identical charges $Q$ are in the vertices of an isosceles triangle according to the diagram below. A fourth charge $q$ is brough from infinity to a location on the center of hypotenuse of the triangle, that is at the point $A=(\frac{L}{2},\frac{L}{2}).$

$L=12cm,Q=2\mathrm{.}5C,q=-33C$

Assuming zero electric potential at infinity, find the electric potential at the point A produced by the $Q$ charges.

What is the work done by an external force to bring $q$ to its final location?

If $q$ is released from rest in which direction will it move to$?$