I need some help on how to calculate electric field vectors at a point called P

[tastybrownies]

Hello everyone and I hope you are enjoying your weekend. I am currently studying for my college physics midterm and got hung up on one of the problems that was on an old midterm.

The problem is as follows: Point charges Q1 = -5uC(micro C) and Q2 = +5.5 uC(micro C) are placed 0.4m apart as shown. The picture shows a 0.4 meter line pointing East, with the positive charge(Q2) on the right and the negative charge(Q1) on the left. Right above Q1, a 0.3 meter line goes North and ends at a point called P.

The drawing is pretty much a right triangle without the hypotenuse line drawn in.

The question wants me to calculate both the x and y components of the total electric field vector at point P. I have one vector line going South and the other going Northwest because of the positive charge. The problem does not give any angles so I'm not sure if they want me to find them or not?

Should I use E = kq/r^2? or Coulomb's Law? I greatly appreciate people for looking at this. I know most of the other problems on this midterm except this one!

 

[tastybrownies]

Actually just figured it out myself. I learned to get the magnitudes of the electric fields first, then you bet I needed the angles for the x and y components. The tricky part was drawing and visualizing the vector angles the correct way, meaning which way i wanted sin or cos to be directed from.

Just in case anyone looked at it, the answers are below.

For magnitude of E1(the 0.3 m) I got 499444.4444. For magnitude of E2(I had to find the hyp of .5 for the r), I got 179800.

I found the bottom right angle of 36.86 deg, and the top north west angle of 53.13 deg. sin53.13 deg * 499444.4444 = -3.99X10^5(direction is down on the y axis)
cos36.86 deg * 179800 = -1.4X10^5(direction is left on the x axis)

Phew that feels good!

 

[Bloodthunder]

Besides, wrong forum mate.