When dealing with speed and velocity in different contexts — whether in transportation, sports, or physics — it’s common to encounter various units of measurement. Miles per hour (mph) and feet per second (ft/s) are both units of speed used in different systems. Miles per hour is often used in the United States for vehicle speeds, while feet per second is more commonly used in physics, engineering, and in countries using the imperial system for smaller, more precise measurements.

Knowing how to convert between these two units is essential for tasks such as understanding speed limits, calculating motion, or comparing the speed of different objects.

Why Convert Miles per Hour to Feet per Second?

The need to convert miles per hour to feet per second often arises in practical scenarios. For example, when you’re driving a car at a certain speed in miles per hour and want to understand that speed in feet per second, or if you are solving problems in physics related to motion, where feet per second is the more appropriate unit. Conversions are also helpful in scientific contexts where more granular measurements of speed are required.

Conversion Formula: Miles per Hour to Feet per Second

To convert miles per hour (mph) to feet per second (ft/s), you need to know the conversion factors for both distance and time. Specifically:

• 1 mile = 5,280 feet
• 1 hour = 3,600 seconds

So the conversion factor from miles per hour to feet per second is:

1 mph = 1 mile/hour × 5,280 feet/mile ÷ 3,600 seconds/hour = 1.46667 ft/s

Thus, the formula to convert miles per hour to feet per second is:

Speed (ft/s) = Speed (mph) × 1.46667

Step-by-Step Guide: Converting Miles per Hour to Feet per Second

1. Identify the speed in miles per hour (mph) that you want to convert.
2. Multiply the number of miles per hour by 1.46667.
3. The result will give you the speed in feet per second (ft/s).

Example 1: Converting 30 mph to ft/s

Let’s say you’re traveling at 30 miles per hour. To convert this to feet per second:

30 mph × 1.46667 = 44 ft/s

So, 30 miles per hour is equivalent to 44 feet per second.

Example 2: Converting 60 mph to ft/s

Now, let’s convert 60 miles per hour to feet per second:

60 mph × 1.46667 = 88 ft/s

So, 60 miles per hour is equivalent to 88 feet per second.

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Miles per Hour vs Feet per Second: Key Differences

Unit	Description	Use
Miles per Hour (mph)	A unit of speed used to measure how far something travels in one hour. 1 mph = 1 mile per hour.	Common in the United States for vehicle speed limits, transportation, and casual speed measurement.
Feet per Second (ft/s)	A unit of speed used to measure the rate of motion in feet per second. 1 ft/s = 1 foot traveled per second.	Often used in physics, engineering, and contexts requiring high precision in motion measurements.

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Frequently Asked Questions (FAQs)

1. How many feet per second is 100 miles per hour?

To convert 100 miles per hour to feet per second:

100 mph × 1.46667 = 146.667 ft/s

So, 100 miles per hour is approximately 146.67 feet per second.

2. Why is the conversion factor 1.46667?

The factor 1.46667 comes from the relationship between miles and feet, and hours and seconds:

• There are 5,280 feet in 1 mile.
• There are 3,600 seconds in 1 hour.

By dividing 5,280 feet by 3,600 seconds, you get 1.46667 feet per second per mile per hour.

3. Can I use this conversion for all speeds?

Yes, the conversion factor of 1.46667 works for any speed in miles per hour. Simply multiply the number of miles per hour by 1.46667 to get the speed in feet per second.

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Quick Conversion Table

Here’s a handy reference table for quickly converting miles per hour (mph) to feet per second (ft/s):

Miles per Hour (mph)	Feet per Second (ft/s)
1	1.46667
5	7.33333
10	14.6667
20	29.3333
30	44
50	73.3333
60	88
100	146.667

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Final Thoughts

Converting miles per hour to feet per second is an easy process when you know the conversion factor. By multiplying the speed in miles per hour by 1.46667, you can quickly and accurately convert to feet per second. Whether you’re working in transportation, physics, or any other field that requires speed measurement, knowing how to convert between these units can be incredibly useful!