Feet Per Second to Light Speed
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Conversion Table

How to convert

1 foot per second (fps) = 1.01671E-09 light speed (ls). Foot Per Second (fps) is a unit of Speed used in Standard system. Light Speed (ls) is a unit of Speed used in Metric system.

Feet per second: A unit of speed

Feet per second (ft/s) is a unit of speed or velocity in the US customary and imperial systems. It measures how fast an object is moving by calculating the distance traveled in feet divided by the time taken in seconds. For example, if a person walks 10 feet in 2 seconds, their speed is 5 ft/s.

How to convert feet per second

Feet per second can be converted to other units of speed or velocity by using simple conversion factors. Here are some common units and their conversion factors:

• Meters per second (m/s): To convert from ft/s to m/s, multiply by 0.3048. To convert from m/s to ft/s, divide by 0.3048. For example, 1 ft/s is equal to 0.3048 m/s, and 10 m/s is equal to 32.8084 ft/s.
• Kilometers per hour (km/h): To convert from ft/s to km/h, multiply by 1.09728. To convert from km/h to ft/s, divide by 1.09728. For example, 1 ft/s is equal to 1.09728 km/h, and 50 km/h is equal to 45.8734 ft/s.
• Miles per hour (mph): To convert from ft/s to mph, multiply by 0.681818. To convert from mph to ft/s, divide by 0.681818. For example, 1 ft/s is equal to 0.681818 mph, and 30 mph is equal to 44 ft/s.
• Knots (kn): To convert from ft/s to kn, multiply by 0.592484. To convert from kn to ft/s, divide by 0.592484. For example, 1 ft/s is equal to 0.592484 kn, and 15 kn is equal to 25.3281 ft/s.
• Inches per second (in/s): To convert from ft/s to in/s, multiply by 12. To convert from in/s to ft/s, divide by 12. For example, 1 ft/s is equal to 12 in/s, and 20 in/s is equal to 1.66667 ft/s.
• Miles per second (mi/s): To convert from ft/s to mi/s, multiply by 0.000189394. To convert from mi/s to ft/s, divide by 0.000189394. For example, 1 ft/s is equal to 0.000189394 mi/s, and 1 mi/s is equal to 5280 ft/s.

Where feet per second are used

Feet per second are mainly used in engineering and aviation to measure the speed or velocity of machines and aircrafts.

For example, the speed of sound in air at sea level is about 343 m/s or about 1125 ft/s.

The maximum speed of a Boeing 747 jet airliner is about 988 km/h or about 2717 ft/s.

The average speed of a bullet fired from a handgun is about 1200 ft/s.

Definition of feet per second

According to the US customary and imperial systems definition, one foot per second is the speed of a body that covers a distance of one foot in a time of one second.

Mathematically, it can be expressed as:

v = s / t

where v is the speed or velocity in feet per second, s is the distance traveled in feet, and t is the time taken in seconds.

History of feet per second

The concept of speed or velocity has been studied since ancient times by philosophers and scientists such as Aristotle, Galileo, Newton, etc.

The foot was originally derived from the Roman foot which was defined as one third of a yard or about 11.65 inches.

The second was originally defined in terms of the Earth’s rotation as one eighty-six thousand four hundredth of a mean solar day.

The combination of these two units resulted in the foot per second as a unit of speed or velocity.

The foot per second was officially adopted as part of the US customary and imperial systems in the late 18th century.

Example conversions of feet per second to other units

Here are some examples of converting feet per second to other units of speed or velocity:

1 ft/s = 0.3048 m/s = 1.09728 km/h = 0.681818 mph = 0.592484 kn = 12 in/s = 0.000189394 mi/s
2 ft/s = 0.6096 m/s = 2.19456 km/h = 1.36364 mph = 1.18497 kn = 24 in/s = 0.000378788 mi/s
5 ft/s = 1.524 m/s = 5.4864 km/h = 3.40909 mph = 2.96241 kn = 60 in/s = 0.00094697 mi/s
10 ft/s = 3.048 m/s = 10.9728 km/h = 6.81818 mph = 5.92482 kn = 120 in/s = 0.00189394 mi/s
20 ft/s = 6.096 m/s = 21.9456 km/h = 13.6364 mph = 11.8496 kn = 240 in/s = 0.00378788 mi/s
50 ft/s = 15.24 m/s = 54.864 km/h = 34.0909 mph = 29.6241 kn = 600 in/s = 0.0094697 mi/s
100 ft/s = 30.48 m/s = 109.728 km/h = 68.1818 mph = 59.2482 kn = 1200 in/s = 0.0189394 mi/s

Light Speed

Definition of Light Speed

Light speed, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). It is the speed at which light waves propagate through vacuum, and also the upper limit for the speed at which any form of matter or energy can travel through space. Light speed is an essential parameter in the theories of relativity and electromagnetism, and has relevance beyond the context of light and electromagnetic waves.

How to Convert Light Speed

To convert light speed to other units of speed, we need to multiply or divide by the corresponding conversion factors. For example, to convert light speed to kilometers per hour, we need to multiply by 3,600, since there are 3,600 seconds in one hour. To convert light speed to miles per hour, we need to multiply by 2.2369362920544, since there are 2.2369362920544 miles in one kilometer.

Here are some examples of how to convert light speed to other units of length in the US Standard system and the SI system:

• To convert c to kilometers per hour (km/h), we multiply by 3,600: c x 3,600 = 1,079,252,848.8 km/h
• To convert c to miles per hour (mph), we multiply by 2.2369362920544: c x 2.2369362920544 = 670,616,629.384 mph
• To convert c to feet per second (fps), we multiply by 3.2808398950131, since there are 3.2808398950131 feet in one meter: c x 3.2808398950131 = 983,571,056.43 fps
• To convert c to knots (kn), we multiply by 1.9438444924406, since there are 1.9438444924406 nautical miles in one kilometer: c x 1.9438444924406 = 582,749,918.284 kn
• To convert c to meters per second (m/s), we use the exact value: c = 299,792,458 m/s
• To convert c to meters per minute (m/min), we multiply by 60, since there are 60 seconds in one minute: c x 60 = 17,987,547,480 m/min

Where Light Speed Is Used

Light speed is used in various fields of science and technology where the properties and behavior of light and electromagnetic waves are studied or applied. For example:

• In astronomy and cosmology, light speed is used to measure astronomical distances and time scales, such as light-years and parsecs. It also determines the observable size and age of the universe and the effects of gravity on light such as gravitational lensing and gravitational redshift.
• In physics and engineering, light speed is used to calculate the energy and momentum of particles and fields using the famous equation E = mc2. It also sets the limit for causality and information transfer in physical systems.
• In communication and navigation, light speed is used to determine the delay and bandwidth of signals transmitted through various media such as optical fibers or radio waves. It also affects the accuracy and precision of measurements based on time-of-flight or Doppler effect methods.

History of Light Speed

The concept of light speed has a long history that spans across different cultures and disciplines. Some of the milestones in its development are:

• In ancient times, many philosophers and scientists assumed that light traveled instantaneously or infinitely fast.
• In the late 17th century, Danish astronomer Ole Romer was the first to demonstrate that light had a finite speed by observing the apparent motion of Jupiter’s moon Io. He estimated that light took about 22 minutes to cross the diameter of Earth’s orbit.
• In the early 18th century, English astronomer James Bradley discovered the aberration of starlight caused by Earth’s motion around the Sun. He used this phenomenon to calculate that light traveled about 10 thousand times faster than Earth’s orbital speed.
• In the late 19th century, French physicist Hippolyte Fizeau and American physicist Albert Michelson conducted various experiments using rotating mirrors or interferometers to measure the speed of light more accurately in air or vacuum.
• In the early 20th century, German-born physicist Albert Einstein proposed the special theory of relativity, which postulated that light speed was constant and independent of the motion of the source or the observer. He also showed that light speed was the maximum speed for any form of matter or energy in the universe.
• In the late 20th century, various methods and standards were developed to define and measure light speed more precisely and consistently. In 1983, the International System of Units (SI) adopted the exact value of 299,792,458 metres per second as the definition of light speed in vacuum.

Example Conversions of Light Speed to Other Units

Here are some examples of how to convert light speed to other units of speed, using the conversion factors given above:

• To convert c to kilometers per hour, we multiply by 3,600: c x 3,600 = 1,079,252,848.8 km/h
• To convert c to miles per hour, we multiply by 2.2369362920544: c x 2.2369362920544 = 670,616,629.384 mph
• To convert c to feet per second, we multiply by 3.2808398950131: c x 3.2808398950131 = 983,571,056.43 fps
• To convert c to knots, we multiply by 1.9438444924406: c x 1.9438444924406 = 582,749,918.284 kn
• To convert c to meters per second, we use the exact value: c = 299,792,458 m/s
• To convert c to meters per minute, we multiply by 60: c x 60 = 17,987,547,480 m/min
• To convert c to centimeters per second, we multiply by 100: c x 100 = 29,979,245,800 cm/s