# Homework Help: Help Finding path of a particle with an intial position and initial velocity

1. May 13, 2012

### ezedvin1

Hi everyone,

I am having trouble finding the answer to a homework problem. I don't seem to understand what the question is exactly asking for. The problem is:

find the path of a particle with an initial position 10er + 1.0eϴ and an initial velocity 0.1er + 0.8eϴ

Last edited: May 13, 2012
2. May 13, 2012

### ppfn

Have you considered using the kinematics for cylindrical coordinates?

3. May 13, 2012

### ezedvin1

the equations I am thinking about using are

Cylindrical coordinates: r, ∅, z
x=rcos∅ y=rsin∅

Spherical Coordinates: r, θ, ∅
x=rsinθcos∅ y=rsinθsin∅ z=rcosθ

I also know an equation for velocity as v=$\dot{r}$er + r$\dot{θ}$eθ

I'm still very confused as to what to do with all these equations to find the path of the particle. Please Help.

Last edited: May 13, 2012
4. May 13, 2012

### ppfn

Those equations look like they are for converting from Cartesian coordinates to cylindrical / spherical coordinates.

Try looking around in your book for the kinematic equations in cylindrical / spherical form. If they aren't in your book you could try going to this link

en.wikipedia.org/wiki/Equations_of_motion

and try looking for them by Crtl+F and typing in what you're looking for.

I haven't ever worked with those coordinate systems and kinematic equations before, otherwise I would be more helpful.