A charge q1 = +8.15 muC is at the origin, and a charge q2 = -3.70 muC is on the x-axis 0.52 m from the origin. Find the electric field strength at point P, which is on the y-axis 0.61 m from the origin.
Answer = [1.613 x 10^5 N/C at 77.979 degrees]
E = kQ/r^2
k = 9.0 x 10^9
tan o = Ey / Ex (?)
C^2 = A^2 + B^2 (?)
Ex = E1 cos 30 (?)
Ey = E2 - E1 sin 30 (?)
The Attempt at a Solution
I used the Pythagorean Theorem to figure out the distance from P to q2, which gave me 0.8 m.
I then went to use E to find E1, which I inputted as
((9x10^9)x(3.7x10^-6))/(0.8^2) = 5.2 x 10^4 N/C
Then E2 as
((9x10^9)x(8.15x10^-6))/(0.61^2) = 2.0 x 10^5 N/C
Ex = E1 x cos 30 = 4.5 x 10^4 N/C
Ey = (E2 - E1) x sin 30 = 7.4 x 10^4 N/C
Then I used Pythagorean Theorem again, thus getting:
E = Square root (4.5^2 + 7.4^2) x 10^4 = 8.7 x 10^4 N/C
Where did I go wrong? or did I do it incorrectly?