Suppose you want to convert miles per hour to feet per second. what conversion factors should you use? how did you determine which units should go, in the numerators, and the denominators of the conversion factors? # suppose you want to convert miles per hour to feet per second. what conversion factors should you use? how did you determine which units should go, in the numerators, and the denominators of the conversion factors?

I'm doing this right now too :)

You start by writing the original numbers given into a proportion, which would be

miles           
      
hours

Then you have to convert the top unit, miles, into feet. You have to use the rate 1mile:5280 feet. You write that as a proportion too.

miles        1
=  ___

hours      5280

Next, you have to add a conversion rate for changing the hours into seconds. You'd use the rate 1 hour: 60 seconds.

miles        1          60
=  ___  = 
hour        5280      1

Then you'd cross multiply to solve.