# Position of a charged particle

https://scontent.fewr1-1.fna.fbcdn.net/v/t34.0-12/14264093_1254405171250525_3984730770686346342_n.jpg?oh=346e65c981cd752be738e3496319668d&oe=57D9DCD3

This would be the magnitude of just F1, correct?

kuruman
Homework Helper
Gold Member
You have misunderstood Coulomb's law. It states that the magnitude of the force between two charges is equal to constant (1/4πε0) times the product of the charges divided by the square of the distance between the two charges. Look at the drawing. What is the square of the distance between q1 and q3? Do NOT use numbers; use the symbols that are shown in the drawing.

You have misunderstood Coulomb's law. It states that the magnitude of the force between two charges is equal to constant (1/4πε0) times the product of the charges divided by the square of the distance between the two charges. Look at the drawing. What is the square of the distance between q1 and q3? Do NOT use numbers; use the symbols that are shown in the drawing.
I sincerely do not know. I thought the distance between q1 and q3 was just SQRT((x^2) + (y^2)).

kuruman
Homework Helper
Gold Member
It is, but I asked you to find the square of that distance. You need the square because it is what appears in the denominator when you write Coulomb's law. So find the square of the distance and divide it into (1/4πε0) times the product of the charges to find F1.

I have to teach my class now, be back in an hour.

It is, but I asked you to find the square of that distance. You need the square because it is what appears in the denominator when you write Coulomb's law. So find the square of the distance and divide it into (1/4πε0) times the product of the charges to find F1.

I have to teach my class now, be back in an hour.
Here is what I have so far. Is this the right process?
https://scontent.fewr1-1.fna.fbcdn.net/v/t34.0-12/14344135_1254552687902440_1826194822450464519_n.jpg?oh=dc4822bd9ff309ed6c57b7d5d10a611b&oe=57D97E88

kuruman
Homework Helper
Gold Member
It's fine, but you really need to learn to use symbols instead of numbers. It's much easier, shorter and neater to write k instead of 9x109, q1 instead of 6x10-9, q3 instead of 2x10-9 and x instead of 0.03. The main reason for this is that it will be much easier to troubleshoot your algebra if something goes wrong. Anyway, now that you have the magnitude of force F1, can you write expressions for its x and y components?

It's fine, but you really need to learn to use symbols instead of numbers. It's much easier, shorter and neater to write k instead of 9x109, q1 instead of 6x10-9, q3 instead of 2x10-9 and x instead of 0.03. The main reason for this is that it will be much easier to troubleshoot your algebra if something goes wrong. Anyway, now that you have the magnitude of force F1, can you write expressions for its x and y components?
To write expressions for the x and y components, would I just move the y to the left hand side and get the expression for just y, and then do the same for x?

kuruman
Homework Helper
Gold Member
I am not sure I understand what you are asking, but you need to end up with a right triangle in which F1 is the hypotenuse, F1x is the horizontal right side and F1y is the vertical right side. Perhaps you can show me a picture before you proceed further.

haruspex