Two point charges are located on the y axis as follows: charge q1 = -2.50nC at y1 = -0.700m , and charge q2 = 3.30nC at the origin (y = 0). What is the magnitude of the net force exerted by these two charges on a third charge q3 = 9.00nC located at y3 = 0.250m ?

Question

What is the direction of the net force?

Answer 1

add them.

forcenet=F1 + F2
= -2.5*9/(.250+.7)^2 + 3.3*9/(.250+0)^2

put units on charges, I ignored that. Direction. think quickly, which force on q3 is greatest, the repulsive, or the attractive.