Unit Conversions: mph to fpsDate: 03/06/2003 at 19:51:58 From: John Subject: Converting miles per hour to feet per second How can I find out how many feet per second I could travel driving 55 miles per hour? Date: 03/06/2003 at 23:33:53 From: Doctor Jeremiah Subject: Re: Converting miles per hour to feet per second Hi John, You thought fractions would never be good for anything! Forget the numbers and concentrate on the units: 55 miles -------- 1 hour What would you multiply this by to cancel the hours? 55 miles hours miles -------- x ----- = ----- 1 hour sec sec What is hours/second? There are 3600 seconds in 1 hour so hours/second = 1 hour/3600 seconds which means: 55 miles 1 hour 55 miles -------- x -------- = -------- 1 hour 3600 sec 3600 sec Now, what would you multiply miles/sec by to get feet/sec? 55 miles feet feet -------- x ---- = ---- 3600 sec mile sec What is feet/mile? There are 5280 feet in 1 mile so feet/mile = 5280 feet/1 mile which means: 55 miles 5280 feet 55 x 5280 feet -------- x --------- = -------------- 3600 sec 1 mile 3600 sec This works for any conversion. You just multiply the fractions that are appropriate and you end up with the answer. In this particular instance, as a check, you can use the fact that 60 miles per hour is the same as 88 feet per second. - Doctor Jeremiah, The Math Forum http://mathforum.org/dr.math/ |
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