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Trigonometry Speed of a Bicycle

karush

Well-known member
Jan 31, 2012
2,752
The tires of a bicycle have radius of $13 \text{ in}$ and are turning at a rate of
$\displaystyle\frac{200\text{ rev}}{\text{min}}$

How fast is the bicycle traveling in
$\displaystyle\frac{\text{mi}}{\text{hr}}$

well my try on this is.

$
\displaystyle 26\pi\text{ in }
\cdot
\frac{200\text{ rev}}{\text {min}}
\cdot
\frac{\text {ft}}{12\text{ in}}
\cdot
\frac{\text {mi}}{5280\text{ ft}}
\cdot
\frac{60\text { min}}{\text{ hr}}
\approx\frac{15.5\text { mi}}{\text{ hr}}
$
no answer given so hope this is it..:cool:
assume "rev" not a unit measure but doesn't cancel out so its not carried thru..
 

Klaas van Aarsen

MHB Seeker
Staff member
Mar 5, 2012
8,797
Re: speed of a Bicycle

The tires of a bicycle have radius of $13 \text{ in}$ and are turning at a rate of
$\displaystyle\frac{200\text{ rev}}{\text{min}}$

How fast is the bicycle traveling in
$\displaystyle\frac{\text{mi}}{\text{hr}}$

well my try on this is.

$
\displaystyle 26\pi\text{ in }
\cdot
\frac{200\text{ rev}}{\text {min}}
\cdot
\frac{\text {ft}}{12\text{ in}}
\cdot
\frac{\text {mi}}{5280\text{ ft}}
\cdot
\frac{60\text { min}}{\text{ hr}}
\approx\frac{15.5\text { mi}}{\text{ hr}}
$
no answer given so hope this is it..:cool:
assume "rev" not a unit measure but doesn't cancel out so its not carried thru..
Yep. That is it.
And indeed, "rev" is not a unit measure - it's dimensionless.
Or if you want, you have $2\pi \cdot 13 \text{ in/rev}$, making it cancel out nicely.
 

karush

Well-known member
Jan 31, 2012
2,752
Re: speed of a Bicycle

Yep. That is it.
And indeed, "rev" is not a unit measure - it's dimensionless.
Or if you want, you have $2\pi \cdot 13 \text{ in/rev}$, making it cancel out nicely.
cool tip..

I am going to start another thread with one that is:confused: to me. I don't understand RAD...