# Homework Help: Rotating coordinate system, velocity

1. Mar 11, 2014

### lemonsare

1. The problem statement, all variables and given/known data

Two coordinate systems xyz (fixed) and x0y0z0 (moving) coincide at time t = 0.
The moving system is rotating about the fixed z axis, which coincides with z0 axis. The angular velocity is given by ω = tk = tk0. The position vector as measured in the rotational frame is equal to
r0 (t) = (t + 1) i0 + t^2 j0:
1. Using the rotating frame find v0.

2. Relevant equations

ω = tk = tk0
r0 (t) = (t + 1) i0 + t^2 j0

3. The attempt at a solution

So i know to find v0, i cannot just differentiate r0. but i am stuck.

2. Mar 11, 2014

### Simon Bridge

Welcome to PF;
v0 is the velocity in the rotating reference frame?
r0 is the position in the rotating frame wrt time?

You also need to differentiate the unit vectors.
See: http://home.comcast.net/~szemengtan/ClassicalMechanics/SingleParticle.pdf [Broken]
section 1.8 (p15)

Last edited by a moderator: May 6, 2017