Here’s a list of speed units used in various measurement systems:

1. Metric System (SI Units):

• Meter per second (m/s) – The base unit of speed in the SI system. It is the distance in meters traveled in one second.
  
  

• Kilometer per hour (km/h) – Commonly used for vehicle speeds in everyday use. It is the distance in kilometers traveled in one hour.
  
  

2. Imperial Units:

• Foot per second (ft/s) – A unit of speed in the Imperial system, where it denotes how many feet are covered in one second.
  
  

• Mile per hour (mph) – A common unit used to measure speed, especially for vehicles, in the Imperial system. It represents how many miles are traveled in one hour.
  
  

3. US Customary Units:

• Foot per second (ft/s) – Used similarly to the Imperial system, where it represents the number of feet traveled in one second.
  
  

• Mile per hour (mph) – The same as in the Imperial system, used primarily in the United States.
  
  

4. Nautical Units:

• Knots (kt) – A unit used in navigation to measure speed, typically for ships and aircraft. 1 knot = 1 nautical mile per hour (approximately 1.852 kilometers per hour).
  
  

5. Other Units:

• Mach (Ma) – A unit used to express speed relative to the speed of sound. Mach 1 is the speed of sound, and any speed above Mach 1 is considered supersonic.
  
  

  • Mach 1 = Speed of sound at sea level, approximately 343 m/s or 1235.5 km/h.
    
    

  • Speeds are often expressed in Mach numbers (e.g., Mach 2 for twice the speed of sound).
    
    

• Kilometer per second (km/s) – Used for very high speeds, especially in astronomy or space science, representing how many kilometers are traveled in one second.
  
  

• Centimeter per second (cm/s) – A smaller unit of speed, where it measures how many centimeters are traveled in one second.
  
  

6. Specialized Units:

• Light year per year (ly/year) – In astronomy, the speed at which light travels over a year. It is often used to express the motion of stars or galaxies. 1 light year = 9.461 trillion kilometers.
  
  

• Furlong per fortnight (furlong/fortnight) – A very specialized unit used mainly in horse racing in some countries, where 1 furlong is 1/8th of a mile, and a fortnight is 14 days.
  
  

Speed Conversion Formulas Between Units:

Here are some conversion relationships between various speed units:

1. Meters per second (m/s) to Other Units:
   
   

   • 1 m/s = 3.6 km/h
     
     

   • 1 m/s = 3.28084 ft/s
     
     

   • 1 m/s = 2.23694 mph
     
     

   • 1 m/s = 1.94384 knots
     
     

   • 1 m/s = 0.002237 Mach
     
     

2. Kilometers per hour (km/h) to Other Units:
   
   

   • 1 km/h = 1000/3600 m/s = 0.27778 m/s
     
     

   • 1 km/h = 0.621371 mph
     
     

   • 1 km/h = 0.53996 knots
     
     

   • 1 km/h = 0.000278 Mach
     
     

3. Miles per hour (mph) to Other Units:
   
   

   • 1 mph = 1.60934 km/h
     
     

   • 1 mph = 1.46667 ft/s
     
     

   • 1 mph = 0.44704 m/s
     
     

   • 1 mph = 0.86898 knots
     
     

   • 1 mph = 0.00268 Mach
     
     

4. Knots (kt) to Other Units:
   
   

   • 1 knot = 1.852 km/h
     
     

   • 1 knot = 0.53996 m/s
     
     

   • 1 knot = 1.15078 mph
     
     

   • 1 knot = 1.68781 ft/s
     
     

   • 1 knot = 0.0023 Mach
     
     

5. Mach (Ma) to Other Units:
   
   

   • 1 Mach = 343 m/s (at sea level)
     
     

   • 1 Mach = 1235.5 km/h
     
     

   • 1 Mach = 767.2 mph
     
     

   • 1 Mach = 1013.3 ft/s
     
     

   • 1 Mach = 1.0 knots
     
     

6. Light Year per Year (ly/year) to Other Units:
   
   

   • 1 ly/year = 9.461 trillion kilometers per year
     
     

   • 1 ly/year ≈ 5.8786 trillion miles per year
     
     

   • 1 ly/year ≈ 63,241.1 AU/year (astronomical units)