Here's how to convert 90 mph to feet per second:

1. Convert miles to feet:

* There are 5280 feet in one mile.

* 90 miles * 5280 feet/mile = 475,200 feet

2. Convert hours to seconds:

* There are 3600 seconds in one hour.

3. Divide the distance (feet) by the time (seconds):

* 475,200 feet / 3600 seconds = 132 feet per second