You run a 100-yd dash in 9.8 seconds. What is your speed in miles per hour?

1 Answer
Nov 13, 2015

Answer:

20.90 mph

Explanation:

This is a problem that is employing conversion and conversion factors.

we'er given a yards per second speed, so need to convert yards to miles and seconds into hours.

#(100 y)/1# ##x## #(5.68E^-4m)/(1 y)# = #.0568 m#

then we convert the seconds into hours

#(9.8 s)# ##x## #(1m)/(60 s)# ##x## #(1 h)/(60 m)# = #.0027 hr#

Now that you have the right units, you can use the speed equation

#S=D/T# = #.0568/.0027# =#20.90 mph#

It's important to note that when I did this calculations I did not round. Therefore, if you were to calculate #.0568/.0027# your answer would be slightly different due to rounding errors.