Constants
π = 3.14159...
e = 2.71828...
Length
1 inch = 2.54 cm 1 meter = 39.37 inch = 3.281 feet
1 foot = 0.3048 meter 12 inches = 1 foot
3 feet = 1 yard 1 yard = 0.9144 meter
1 kilometer = 0.621 mile 1 mile = 1.609 kilometer
1 mile = 5280 feet 1 Å = 10-10 meter
1 μm = 1 μ = 10-6 m = 104 Å 1 lightyear = 9.461 x 1015 m
Area
1 m2 = 106 cm3 = 10.76 ft2 1 ft2 = 0.0929 m2 = 144 inches2
1 inches = 6.452 cm2
Angle
1 radian = 57.296 degrees
1 degree = 0.0175 radian
Volume
1 m3 = 10 cm3 = 6.102 x 104 inches3
1 ft3 = 1728 inches3 =2.83 x 10-2 m3
1 liter = 1000 cm3 = 1.0576 qt = 0.0353 ft3
1 ft3 = 7.481 gal = 28.32 liters = 2.832 x 10 m3
1 gal = 3.786 liters = 231 inches3
Mass
1000 kg = 1 t (metric ton) 1 slug = 14.59 kg
1 u = 1.66 x 10-27 kg
Force
1 N = 105 dyne = 0.2248 lb 1 lb = 4.448 N
1 dyne = 10-5 N = 2.248 x 10-6 lb
Velocity
1 mi/h = 1.47 ft/s = 0.447 m/s = 1.61 km/h
1 m/s = 100 cm/s = 3.281 ft/s 1 mi/min = 60 mi/h = 88 ft/s
Acceleration
1 m/s2 = 3.28 ft/s2 = 100 cm/s2 1 ft/s2 = 0.3048 m/s2 = 30.48 cm/s2
Pressure
1 bar = 105 N/m2 = 14.50 lb/inches2 1 atm = 760 mm Hg = 76.0 cm Hg
1 atm = 14.7 lb/inches2 = 1.013 x 105 N/m2
1 Pa = 1 N/m2 = 1.45 x 10 lb/inches2
Time
1 year = 365 days = 3.16 x 107 s
1 day = 24 h = 1.44 x 103 min = 8.64 x 104 s
Enegry
1 J = 0.738 ft*lb = 107 erg 1 cal = 4.186 J
1 Btu = 252 cal = 1.054 x 103 J 1 eV = 1.6 x 10-19 J
931.5 MeV/c2 = 1 u 1 kWh = 3.60 x 106 J
Power
1 hp = 550 ft*lb/s = 0.746 kW 1 W = 1 J/s = 0.738 ft*lb/s