mathmatics 1 worksheet: converting ft/sec to mph

[clueless_freshmeat2092]

Please help me! :?

6. In an offshore pipeline, a cylindrical mechanism called a "pig" is run through the pipes periodically to clean them. These pigs travel at 2 feet per second. What is this speed expressed in miles per hour?

I know I need to find something with mph, but I don't know how. Can someone help me?

thanks,
:idea: clueless :shock:

 

[stapel]

Work step-by-step. If the speed is two feet in one second, how many feet is that per minute? Then how many feet per hour? Then how many miles are in that many feet?

Eliz.

 

[jonboy]

You can do it the Eliz way or you can set up a proportion.


Since 1 hr equal 3,600 seconds:


\(\displaystyle \L \frac{2}{1}\,\bullet\,\frac{x}{3,600}\)


Notice how everything is in the same units and proportional.


Cross multiply to get:\(\displaystyle \L \;x\,=\,7,200\)


So the speed is \(\displaystyle \L \;7,200\;mph\)

 

[galactus]

Jonboy, my dear boy, that is one fast 'pig'(Mach 10). You'd better look again. I think you missed a step to get Miles Per Hour

 

[jonboy]

Jonboy, my dear boy, that is one fast 'pig'(Mach 10). You'd better look again. I think you missed a step to get Miles Per Hour

Goshdangit ok. Sry about that. Just use Stapel's approach it is much better.

 

[galactus]

No biggie, just an oversight. Just divide by 5280.

 

[skeeter]

good rule of thumb to learn ...

15 miles/hr = 22 ft/sec

so ...

(15 mph)/(22 ft/s) = (x mph)/(2 ft/s)

x = 30/22 = 15/11 mph

 

[soroban]

Hello, all!

Years ago, I derived the conversion and memorized it: \(\displaystyle \,60\,\text{mph }\,=\;88\,\text{ft/sec}\)

You can derive it yourself using the standard conversions:
\(\displaystyle \;\;\;\begin{array}{ccc}1\text{ mile}\;=\;5280\text{ feet} \\1\text{ hour}\;=\;60\text{ minutes} \\1\text{ minute}\;=\;60\text{ seconds}\end{array}\)

Then:\(\displaystyle \,60\,\text{mph} \;=\;\frac{60\,\sout{\text{miles}}}{1\,\sout{\text{hour}}}\,\times\,\frac{5280\text{ feet}}{1\,\sout{\text{mile}}} \,\times\,\frac{1\,\sout{\text{hour}}}{60\,\sout{\text{minutes}}}\,\times\,\frac{1\,\sout{\text{minute}}}{60\text{ seconds}} \;=\;\frac{88\text{ feet}}{1\text{ second}}\;=\;88\,\text{ft/sec}\)