Electric Field Question?

Question

Three charges are at the corners of an
equilateral triangle, measuring 0.5 m on
each side. The charges are:
q1= 2 μC, q2= 7 μC, q3 =-4 μC
1. Calculate the electric field at the position
of the 2 μC due to q2 and q3.
2. Use the field to determine the force on
q1.

Answer 1

q1-------q2


------q3

F1,2= k q1q2/R^2
F1,3= k q1q3/R^2
E1,2= F1,2/q1= k q2/R^2
E1,2= F1,3/q1= k q3/R^2

X-component
Ex=-E1,2 + E1,3 cos(60)
Y- component
Ey= E1,3 sin(60)

Et1= sqrt[(Ex)^2 + (Ey)^2]
angle = arctan(Ey/Ex)

b) F1= Et1 q1