I've been thinking a bit more about my answer and realised I could explain a bit more about why the scaling factors etc. can be ignored.
firstly the 3 cm.
The measuring unit is actually quite arbitrary, we could use inches or parsecs or...
I choose to use quogs, which I have just invented for the occasion.
one quog happens to be exactly 3 cm.
This has the advantage that the the scaling factor becomes 1 and so become trivial and disappears from the problem.
Similarly the omega in the equation is scaling factor between time and and the wavelength of the motion.
choose ticks (of just the right length) instead of seconds and omega disappears.
(note that the use of degrees or radians is also just a scaling factor, I chose to use degrees in my answer simply because that is the default setting on my calculator).
Finally, phi is an offset, which indicates when you started timing with respect to the cycle of the motion.
In a real experiment this would be important, but the advantage of a thought experiment is that you can start your stopwatch whenever you like.
If you start your stopwatch at precisely the start of the cycle, then phi will be zero and disappears from the problem.
so work out the problem using ticks and quogs with a perfect click of the stopwatch.
Only at the end do you need to re-scale your answer from quogs to centimetres.
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Last edited by MBW; Apr 11th 2015 at 03:13 AM.
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