This list of mechanical constants represent the most common values used in engineering,
physics, and chemistry.
Visit NIST for all
constants, units, and uncertainties. This is their
Extensive Listing
of constants.
Horsepower 
HP 
745.7 W 
Atmosphere 
Atm 
14.70 lb/in^{2} 
Pi 
P 
3.141 592 653 589 793 238 46 
Natural log base 
e 
2.718 281 828 459 045 235 36 
Square root of 2 
√2 
1.414 213 562 372 095 048 80 
Euler's constant 
g 
0.577 215 664 901 532 860 61 
Golden Ratio 
f 
1.618 033 988 749 894 848 20 
1º of latitude at 40º latitude 

69 mi 
Acceleration of gravity 
g 
32.1726 ft/s^{2} 
Knot 
kt 
1.1508 mi/hr 
Speed of sound @ 0ºC 

1087.1 ft/s 
Water heat of fusion @ 0ºC 
∆H_{fus} 
79.71 cal/g 
Water heat of vaporization @ 0ºC 
∆H_{vap} 
539.55 cal/g 
Acre 

43 560 ft^{2} 
