Question 715250: A wheel with a 18-inch diameter is turning at the rate of 48 revolutions per minute. To the nearest inch, what is the speed of a point on the rim in in/min.? I just need a formula or sample to get the answer, just stuck and can't figure it out.
Answer by DrBeeee(684)   (Show Source):
You can put this solution on YOUR website! A point on the rim travels a distance, c, equal to the circumference of the wheel of diameter, d, for each revolution of the wheel. Correct?
Then we have
(1) c = pi*d in/rev or
(2) c = 18*pi in/rev
Now multiply (2) by the turning rate of 48 rev/min to get the speed, s,
(3) s = (18*pi in/rev)*(48 rev/min) or
(4) s = 18*48*pi in/min or
(5) s = 2714 in/min
Note that in (3), when you multiply the units together, (1/rev)*rev equals one, and we get
(6) (in/rev)*(rev/min) = in/min
This is called dimensional analysis - get to learn it.
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