- #1
naphtalene
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Homework Statement
I don't know exactly how to integrate in this case.
This problem is about the track (spiral) of a spinning CD in a player.
The radius of the spiral depends on time/revelations and is given by:
[itex]r=r_i+\frac{h\theta}{2\pi}[/itex] , which means that the radius increases with h per revelation.
v ist the constant speed with which the disc surface passes the laser. The rate of change of the angle is given by:
[itex]\omega = \frac{d\theta}{dt} = \frac{v}{(r_i + \frac{h\theta}{2\pi} )}[/itex]
I am looking for the angle as a function of time.
[itex]\int \! \omega \, dt = \int \! \frac{v}{r_i+\frac{h\theta}{2\pi}} \, dt = ?[/itex]
Homework Equations
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The Attempt at a Solution
Well, I tried to substitute [itex]\theta[/itex] with [itex]\omega t[/itex] but this is definitely wrong because neither the angular velocity nor the angular acceleration is constant.
Now I'm really stuck ...I'm somewhat slow on the uptake tomorrow. Any hints? How can I solve this?