How fast is 5.8 sec in the 40 yard dash in mph?

40 yrds. equals 120 ft. divide 120 ft. by 5.8 sec. equals 20.69 fps. Multiply 3600 seconds in an hour by 20.69 fps. equals 74,484 ft per hr. Now divide 74,484 fph by 5280 ft in a mile. Your speed is 14.10 MPH.