Fps Engineering Units

In some countries a nondecimal gravitational unit system has long been used in commerce and engineering. The system can be derived from the SI system by making the following decisions. 

The standard for length is the inch (in.), defined as 2.54 cm. This is equivalent to defining the foot (ft) as 

The thermodynamic temperature scale is called the Rankine scale, in which temperatures are denoted by degrees Rankine and defined by 

The analog of the Celsius scale is the Fahrenheit scale, in which readings are denoted by degrees Fahrenheit. It is derived from the Rankine scale by setting its zero point exactly 32°F below the ice point on the Rankine scale, so that 

The relation between the Celsius and the Fahrenheit scales is given by the exact equation 

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