If a bullet is fired at 2398ft/s and we wish to convert that to miles/hr, we need to do some conversions first. We know that there are 60 seconds in 1 minute. So we multiply each side of the equation by 60. This gives us 143,880 ft/min. We also know that there are 60 minutes in an hour. So we again multiply each side by 60. This gives us 8,632,800ft/hr. We know that there are 5,280 ft in a mile. So we can divide 8,632,800 by 5280. This gives us our final answer of 1,635 miles/hr.