(1) It's always OK to multiply by 1... All unit conversions make use of this fact...
(2) Units cancel. Unit conversions make use of this fact, too...
As an example, let's assume you're trying to calculate the length, in ms, of 27 beats of a song at a tempo of 140 bpm. You're trying to convert beats to ms - a unit conversion.
Note that 60sec/minute and 1000ms/sec both equal one, since top & bottom are equivalent. Note that for a song of 140bpm, the "per" in bPm is telling you that the top and bottom are equal, too...
Thus, the formula:
length in ms = beats x (minute/beats) x (secs/minute) x (ms/sec)
...helps you calculate ms by taking your # of beats & multiplying by 1 a few times to accomplish unit conversions (rule #1 above). Note that beats, minutes & secs all cancel (rule #2 above), leaving you with ms.
So, how many ms are in 27 beats at 140bpm???
ms = 27 beats x (1min/140beats) x (60sec/1min) x (1000ms/sec)
= (27x1x60x1000)/140
= 11571.43 ms
Hope this helps...Statistics: Posted by shawnb — 12 Jun 2016, 21:56
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