# Unit Conversion Factors

Length

1 m = 100 cm = 1000 mm = 109 nm

1 km = 1000 m = 0.6214 mi

1 m = 3.281 ft = 39.37 in.

1 cm = 0.3937 in.

1 in. = 2.540 cm

1 ft = 30.48 cm

1 yd = 91.44 cm

1 mi = 5280 ft = 1.609 km

1 Å = 10-10 m = 10-8 cm = 10-1 nm

1 nautical mile = 6080 ft

1 light@year = 9.461 * 1015 m

Area

1 cm2 = 0.155 in.2

1 m2 = 104 cm2 = 10.76 ft2

1 in.2 = 6.452 cm2

1 ft2 = 144 in.2 = 0.0929 m2

Volume

1 liter = 1000 cm3 = 10-3 m3 = 0.03531 ft3 = 61.02 in.3

1 ft3 = 0.02832 m3 = 28.32 liters = 7.477 gallons

1 gallon = 3.788 liters

Time

1 min = 60 s

1 h = 3600 s

1 d = 86,400 s

1 y = 365.24 d = 3.156 * 107 s

Angle

1 rad = 57.30       = 180    >p

1 revolution = 360              = 2p rad

1 rev>min 1rpm2 = 0.1047 rad>s

Speed

1 m>s = 3.281 ft>s

1 ft>s = 0.3048 m>s

1 mi>min = 60 mi>h = 88 ft>s

1 km>h = 0.2778 m>s = 0.6214 mi>h

1 mi>h = 1.466 ft>s = 0.4470 m>s = 1.609 km>h

1 furlong>fortnight = 1.662 * 10-4 m>s

Acceleration

1 m>s2 = 100 cm>s2 = 3.281 ft>s2

1 cm>s2 = 0.01 m>s2 = 0.03281 ft>s2

1 ft>s2 = 0.3048 m>s2 = 30.48 cm>s2

1 mi>h # s = 1.467 ft>s2

Mass

1 kg = 103 g = 0.0685 slug

1 g = 6.85 * 10-5 slug

1 slug = 14.59 kg

1 u = 1.661 * 10-27 kg

1 kg has a weight of 2.205 lb when g = 9.80 m>s2

Force

1 N = 105 dyn = 0.2248 lb

1 lb = 4.448 N = 4.448 * 105 dyn

Pressure

1 Pa = 1 N>m2 = 1.450 * 10-

4 lb>in.2 = 0.0209 lb>ft2

1 bar = 105 Pa

1 lb>in.2 = 6895 Pa

1 lb>ft2 = 47.88 Pa

1 atm = 1.013 * 105 Pa = 1.013 bar

= 14.7 lb>in.2 = 2117 lb>ft2

1 mm Hg = 1 torr = 133.3 Pa

Energy

1 J = 107 ergs = 0.239 cal

1 cal = 4.186 J 1based on 15            calorie2

1 ft # lb = 1.356 J

1 Btu = 1055 J = 252 cal = 778 ft # lb

1 eV = 1.602 * 10-19 J

1 kWh = 3.600 * 106 J

Mass–Energy Equivalence

1 kg48.988 * 1016 J

1 u4931.5 MeV

1 eV41.074 * 10-9 u

Power

1 W = 1 J>s

1 hp = 746 W = 550 ft # lb>s

1 Btu>h = 0.293 W