# Cylindrical coordinates

1. Sep 11, 2008

### Carol_m

Hello there,

I was wondering if someone can help me with this problem.

I have different charges distributed in the space as a cylinder. The axis of the "cylinder" is the Y axis. And I have one charge at certain distance (let s say pp) from the "cylinder", how do I calculate the vector from this charge to each particle (in cylindrical coordinates)?

Also, how do I calculate the vector from one particle to another in cylindrical coordinates?.

At the moment I have define the vector as $$\vec{R}$$=R$$_{\rho}$$$$\hat{\rho}$$+R$$_{\varphi}$$$$\hat{\varphi}$$+R$$_{y}$$$$\hat{y}$$

where R$$_{\rho}$$=R*sin($$\frac{\varphi2-\varphi1}{2}$$), R_phi=R*cos($$\frac{\varphi2-\varphi1}{2}$$) and R$$_{y}$$=y1-y2

R=sqrt(radius^2-2*radius^2*cos($$\varphi$$2-$$\varphi$$1)),
y1 and y2 is the respectively distance to the centre and $$\varphi$$2, $$\varphi$$1 is the angle of each particle regarding axis X.

ps. sorry if my notation is not very good but I am new in this forum and I am not sure how this works!
Hope I explain myself clear enough! :)