Rocket Propulsion Elements, 9th Edition

APPENDIX 1CONVERSION FACTORS AND CONSTANTS

Conversion Factors (arranged alphabetically)

Acceleration (L t⁻²)¹

• 1 m/sec² = 3.2808 ft/sec² = 39.3701 in./sec²
• 1 ft/sec² = 0.3048 m/sec² = 12.0 in./sec²
• = 9.80665 m/sec² = 32.174 ft/sec² (standard gravity constant at Earth's surface)

Area (L²)

• 1 ft² = 144.0 in.² = 0.092903 m²
• 1 m² = 1550.0 in.² = 10.7639 ft²
• 1 in.² = 6.4516 × 10⁻⁴ m²

Density (M L³)

• Specific gravity is dimensionless, but has the same numerical value as density expressed in g/cm³; 1 liter = 10⁻³ m³
• 1 kg/m³ = 6.24279 × 10⁻² lbm/ft³ = 3.61273 × 10⁻⁵ lbm/in.³
• 1 lbm/ft³ = 16.0184 kg/m³
• 1 lbm/in.³ = 2.76799 × 10⁴ kg/m³

Energy, also Work or Heat (M L²t⁻²)

• 1.0 Btu = 1055.056 J (joule)
• 1.0 kW‐hr = 3.600 × 10⁶ J
• 1.0 ft‐lbf = 1.355817 J
• 1.0 cal = 4.1868 J
• 1.0 kcal = 4186.8 J

Force (M Lt^‐ 2)

• 1.0 lbf = 4.448221 N
• 1 dyne = 10⁻⁵ N
• 1.0 kg (force) [used in Europe] = 9.80665 N
• 1.0 ton (force) [used in Europe] = 1000 kg (force)
• 1.0 N = 0.2248089 lbf
• 1.0 millinewton (mN) = 10⁻³ N
• Weight is the force acting on a mass being accelerated by gravity ( applies at the Earth's surface)

Length (L)

• 1 m = 3.2808 ft = 39.3701 in.
• 1 ft = 0.3048 m = 12.0 in.
• 1 in. = 2.540 cm = 0.0254 m
• 1 mile = 1.609344 km = 1609.344 m = 5280.0 ft
• 1 nautical mile = 1852.00 m
• 1 mil = 0.0000254 m = 1.00 × 10⁻³ in.