You are running 15.5 miles per hour.
As speed as
125.58 mph
1 miles = 5280/3 yards = 1760 yards. 50 yards / 1760 yards/mile ~= 0.02841 miles 7.2 seconds / 3600 seconds/hour ~= 0.002 hours 0.02841 miles / 0.001833 hours ~= 14.2 miles per hour In general divide 102.27 by your time in seconds to get mph.
About 638 mph
You are going at approx 0.18 miles per second = 643 mph.
On average you will be going around 18.75mph
Approximately 8 seconds
You are running 23.31 miles per hour.
Hines Ward's 40 yard time is 4.55 seconds.
20 meters per second
Eleven seconds
About 4.5 miles per hour.