posted by ali .
Three spheres, each with a negative chrge of 4.0x10^6C, are fixed at the vertices of an equilateral triangle whose sides are 0.20 m long. Calculate the magnitude and direction of the net electric force on each spehere.
i used this: (K)Cos30((4.0*10-6)*2)/(0.2*2)
and i get 3.1 every time...
^ means exponent
multiply by 2, there are two electrons acting on the third
I get 3.6 Newtons - see my solution where you first posted the question