Electromagnetism problem-ΣE on a point

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cotsiospower
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Homework Statement


Hi. I need help with the problem attached. I need to find the ΣE of the point and the direction angle... All information needed are on the attachment...


2. Homework Equations [


The Attempt at a Solution


There is no attempt since the teacher said nothing relevant... :(
 
Attachments
  • Diagram of a rectangle with dashed sides: q1 = 10 µC (blue dot) at the top left, q2 = -10 µC (red dot) at the top right, q3 = -10 µC (red dot) at the bottom left, and an unlabeled grey point at the bottom right. The top side is labeled 4 cm and the left side 3 cm.
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cotsiospower said:

Homework Statement


Hi. I need help with the problem attached. I need to find the ΣE of the point and the direction angle... All information needed are on the attachment...


2. Homework Equations [


The Attempt at a Solution


There is no attempt since the teacher said nothing relevant... :(


If the teacher hasn't stated anything relevant, then there's always the textbook :smile:

What formulas have you learned regarding electric charges?
 
the only thin i found is: E=(k*|q|)/r*r
where k=9*10^9
Any idea?
 
cotsiospower said:
the only thin i found is: E=(k*|q|)/r*r
where k=9*10^9
Any idea?

That is an expression that gives you the magnitude of the electric field due to a point charge (q) at some distance r. It's useful, and is almost right for what you need here.

A closely related expression gives the force that acts between two charges separated by distance r. Multiply the field that the above expression gives you by a second charge, say Q, and you get the force that each charge exerts on the other.

At this point I would suggest that you check your text or even investigate on the web the concept of "the force between electric charges". You will also need to learn about force vectors and the addition of vectors. These are some basic concepts there that you will need in order to solve this problem.