3 charges -q,q,q are placed at 3 vertices of an equilateral triangle of side 0.4 cm. The magnitude of the charges is 8mc.A charge Q is placed at the centroid.Find the force acting on Q

To calculate the distance between charge Q and the charges at vertices you`ll have to peek into centre of mass The centre of mass or centroid lies at a (2h|3)distance of from any vertice The force comes out to be 6Qx10^12(SI units)