Calculating the magnitude of the total electric field at P

[ddobre]

Homework Statement

Two electric charges each produce electric fields. At a certain point in space P, the electric field due to the first charge has a magnitude of 8 N/C, and points directly to the right. The electric field at that point due to the second charge has a magnitude of 3 N/C, and points directly up.

(a) What is the magnitude of the total electric field at point P

(b) If an object with a charge of 0.83 coulombs is placed at point P, what is the magnitude of the force it will experience?

Homework Equations

E = k(Q/(r^2))
E = F/q

The Attempt at a Solution

I tried drawing the diagram to get a better understanding of the direction of the fields. I know that I should probably be breaking the vectors into components, but I am having issues due to the lack of information provided in the problem. But, if the charges point directly right towards the point P, and directly up towards P, could I not add the magnitudes of the electric field? I attempted this, finding the answer to be incorrect. I also thought perhaps since I don't have the radius I could try to relate equations to solve for it and other unknown variables, but I found that I could not relate the terms.

 

[harambe]

Okay
You can't just add electric fields because they are vectors.You need to know the angle between them.

What is the angle between the electric fields at point P

 

[berkeman]

I tried drawing the diagram to get a better understanding of the direction of the fields. I know that I should probably be breaking the vectors into components, but I am having issues due to the lack of information provided in the problem.

They gave you the magnitudes and directions of the two vectors. Just add them vectorially (place them nose-to-tail)...

 

[ddobre]

Right, it was a simple case of vector addition. I have not done that in so long I suppose I forgot it was an option. In any case, the nose-to-tail method worked fine, and the second part was simple enough to find after that. Thank you for the help