Three charged particles with q1= -50 nanocoulomb, q2= +50 nanocoulomb, q3= +30 nanocoulomb are placed in a triangle. q1 and q2 are 10 cm apart horizontally and q3 is exactly between the two charges. q3 is 5cm below both q1 and q2. What is the net force on charge q3 due to the other two charges?