# Charged particles and cylindrical coordinate system

1. Sep 16, 2010

### Ry122

A charged particle in a magnetic field is spiralling along a path defined in cylindrical coordinates by r
= 1 m and θ = 2z rad (where z is in meters). The speed along the path is constant at 3.87 km/s. What is
the z-component of the velocity, vz, in cylindrical coordinates?

My attempt: I'm just needing someone to point me in the right direction as to what equations to use here, and how to make use of cylindrical coordinates.

2. Sep 16, 2010

### gabbagabbahey

What is the general expression for position in cylindrical coordinates? How about velocity?