Constants

 

Unit	Type	Description
Absolute Zero	Temperature	-273.16° C -459.69° F 0° K (Kelvin)
Gravity (Earth)	Acceleration	32.174 ft/sec2 9.8 m/sec2
Gross	Quantity	144 (1 dozen dozen or 122)
Knot	Speed	1.15 statute miles per hour (1 nautical mile per hour)
Light Speed	Speed	186,000 miles/sec 299,792,458 m/sec
Light Year	Distance	distance light travels in a year 9,461,000,000,000 km (5,880,000,000,000 mi)
Pi	Ratio	3.141592653589793238 circumference/diameter
Ream	Quantity	500 sheets typically used for paper
Sound Speed	Speed	1,088 ft/sec = Mach 1 (in air@STP)