I am counting how long it takes for a motor to make one revolution, and I would like to express that as revolutions per minute.
"Normally" one would count the revolutions made in one second, and multiply that up to revolutions per minute. However this is not an accurate measurement. (ie. I could record 9 revolutions a second, but there could be anything from 9.1 revolutions to 9.9 revolutions in that second, I would not know) So I am counting the milliseconds it takes the motor to do one revolution, and want to re-calulate that to RPM for readability. How would I do that ?
One minute is $60$ seconds or $60000$ milliseconds. One revolution in $t$ milliseconds means $60000$ revolutions in $t$ minutes, or $60000/t$ revolutions per minute.