1. Convert feet to miles:

* There are 5280 feet in 1 mile.

* Divide 30 ft by 5280 ft/mile: 30 ft / 5280 ft/mile = 0.00568 miles

2. Convert seconds to hours:

* There are 3600 seconds in 1 hour.

* Divide 1 second by 3600 seconds/hour: 1 second / 3600 seconds/hour = 0.000278 hours

3. Calculate mph:

* Divide the distance in miles (0.00568 miles) by the time in hours (0.000278 hours): 0.00568 miles / 0.000278 hours = 20.43 mph

Therefore, 30 ft per second is approximately equal to 20.43 mph.