Sthènes to Pounds-force (sn to lbf)
1 sthène equals 224.8089431 pounds-force (rounded).
How to convert sthènes to pounds-force
To convert sthènes to pounds-force, multiply the number of sthènes by 224.8089431. The factor is rounded to 10 significant digits. To go the other way, multiply pounds-force by 0.004448221615 (rounded).
pounds-force = sthènes × 224.8089431
Example: 10 sthènes = 2,248.089431 pounds-force.
About these units
Sthène (sn)
Exactly 1,000 newtons. The force unit of the old French meter-tonne-second (MTS) system, in use from 1919 until the SI.
The word sthène comes from the Ancient Greek sthenos, meaning force or strength. A British Association committee proposed the unit in 1876 under the name funal, and by 1914 it was being called the sthène. France made it legal in 1919 as the force unit of the metre-tonne-second (MTS) system, and a 1920 report in Scientific American Monthly noted the adoption.
One sthène is the force that gives a mass of one tonne an acceleration of one metre per second squared, so it equals exactly 1,000 newtons, or one kilonewton. In older units that is about 101.97 kilograms-force or 224.8 pounds-force. It was meant for engineering work where the newton, or its CGS predecessor the dyne, gave awkwardly small or large numbers.
The Soviet Union also used the MTS system between 1933 and 1955. It was later abandoned in favour of the metre-kilogram-second system and superseded by the SI, in which the same force is simply written as a kilonewton. Related MTS units include the pièze for pressure and the sthène-metre for energy.
1 sthène = 1,000 newtons (exactly).
Sources: Wikipedia: Sthène; Wikipedia: Metre-tonne-second system of units
Pound-force (lbf)
Exactly 4.4482216152605 newtons: the weight of a one-pound mass under standard gravity. The US unit of force.
People have used the pound-force since the eighteenth century for low-precision work, long before anyone needed to define it carefully. A pound of material on Earth's surface pulls with about a pound of force, which made it convenient to treat the two as one. The twentieth century demanded a precise definition: one pound-force is the avoirdupois pound, exactly 0.45359237 kg, multiplied by standard gravity of 9.80665 meters per second squared, which comes to about 4.448 newtons.
Because the unit is not simply mass times acceleration in its own system, formulas in English engineering units need a conversion constant of about 32.174 pound-feet per pound-force second squared. A slug, 32.174049 pounds of mass, is what one pound-force accelerates at one foot per second squared. In the US, jet and rocket thrust is often given as pounds of thrust: each Space Shuttle solid rocket booster produced 3,300,000 pounds-force. Earth's gravity varies by up to about half a percent between equator and pole, which low-precision work can ignore.
1 pound-force = 4.448221615 newtons (approximately).
Sources: Wikipedia: Pound (force); NIST Guide to the SI, Appendix B.8: conversion factors
Related conversions
- Pounds-force to sthènes (reverse)
- Sthènes to newtons
- Sthènes to kilonewtons
- Newtons to pounds-force
- Kilonewtons to pounds-force
- Kilograms-force to pounds-force
- Meganewtons to pounds-force
- Millinewtons to pounds-force
- Ounces-force to pounds-force
- Grams-force to pounds-force
- Poundals to pounds-force
- Dynes to pounds-force
- Kips to pounds-force
- Tons-force (short) to pounds-force
- Tons-force (long) to pounds-force
See all force units.