Convert 25 m/s into mph. (Use the fact that there are about 1609 m in a mile.) Round appropriately.
5 Answers


Whenever I have to convert from one system to another I use an old trick that used to be taught in chemistry. Put your beginning information down and then use conversion factors to get to what you want. The conversion factors should “cross” out something in the mix. So you have to go from m/s to m/h; we will have to convert from meters to miles and from seconds to hours.
Use the following:
25m  1 mile  60 sec  60 min
——————————————— =
sec 1609 m 1 min  1 hour
your meters, seconds, and minutes cross out and you are left with miles / hours for your units. On the math end, it would be (25*1*60*60)/(1609*1*1) = 90000/1609 = 55.935
I hope you see how to make the horizontal and vertical “placeholders” because my typing skills are not the best.
By changing only one unit at a time and using the chart, you will not get lost.
I hope this helps and please use this method and see if it makes sense.

You’re lucky, when I had to do these, they were in./sec.
Okay, let’s set up a formula.
25 m
—— now you have to make the seconds into minutes. 60
1s seconds in 1 minute
25m 60sec.
—– * ——– the two labels, “sec.” cancel out.
1sec. 1 min,
Now, you have to make 60 minutes in 1 hour.
25m 60 sec. 60 min.
——* ——– * —— The “min.” cancel out. Now you
1 sec. 1 min. 1 hr. have how many meters per hour, but you want it into miles not meters.
So you try to cancel out the meters sign to make make it into miles.
25m 60 sec. 60 min. 1 mile
—– * ——— * ——– * —— now you multiply all of them.
1 sec. 1 min. 1 hr. 1609 meters
90000 meters
——— are you done? No, not yet.
1609 hrs.
Now you have to divide. it is 55.935364 miles per hour.. You can round to nearest whatever you teacher made you round.
It isn’t very hard. Really easy to do.

25meters x 60 x 60=3356.12
3356.12/1609=55.9
answer=55.9 mph

1 hour = 3,600 seconds
25 meters per second = 25/1609 miles per second = about 0.01554 miles per second
0.01554*3,600 = about 55.9356 miles per hour
ANSWER: 55.9356 miles per hour