MathBench > Measurement

Follow the Units

A longer conversion

So, next time you get stuck on a highway doing a bit under 5 miles an hour, just whip out your calculator, do a few conversions, and you'll be amazed how much better you feel.

Not feeling it yet? OK, how about converting 4.5 miles/hour into inches per second?

How many conversions will you need?

It would be a great idea to write the conversion chain now, before you click on the button below...

This looks like a lot of button-pushing on your calculator, but really it's not. You can ignore the units (make sure they cancel correctly by hand though!!!) and also ignore any 1s. If the number is on the "top" of a fraction, use multiplication. If it's on the "bottom", use division. No parentheses needed.

So, what you actually need to type is this:

4.5 * 5280 * 12 / 60 / 60 = 79.2 inches/second!!

One more question: Wouldn't it be a (boat)load easier to just figure out one grand conversion factor???!!!

Yes, that could be easier. So, just in case you ever need to convert miles per hour to feet per second again, just remember, multiply by 17.6

OK, but seriously, if I had to do a bunch of conversions with the same units, I would certainly figure out a conversion factor. But, for a single conversion, no matter how complicated, you should be able to do this quickly and easily. Or, more specifically, you should not need your lab book to provide a conversion factor! Ever! For anything! (And if you think there is a unit out there too obscure for Google, give it a try. Email me if you find one!)