Answer:
63 miles / hour = 0.0175 miles / second
Explanation:
63 miles per hour also equals 0.0108225108225108 feet per second.
Which does not really help you if you don't know how to convert feet per second to miles per second.
How to convert miles per hour to miles per second is fairly easy, with a calculator.
1 mile per hour equals 0.000277777778 miles / second,
and if you multiply 0.000277777778 by 63, you get = 0.01750000001
Which can be rounded to get 0.0175
Hope this helps! <3