I am trying to work the following problem;(adsbygoogle = window.adsbygoogle || []).push({});

A rigid body is rotating about a fixed axis with a constant angular velocity ω. Take ω to lie entirely on th z-axis. Express r in cylindrical coordinates, and calculate;

a) v=ω × r

b)∇ × v

The answer to (a) is v=ψωρ and (b) is ∇ × v = 2ω

Firstly, I am not sure if we need r=[ρcosψ, psinψ, z] or simply [p, ψ, z]. Secondly, are they saying that ω is simply [0, 0, ω]? if so then I don't get the result so I am doing something wrong. Any help? I am sure that tackling this problem will deepen my understanding of curvilinear coordinates.

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# Homework Help: Vector product question in cylindrical coordinates

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