Convert from livre [France] to slinch

Unit Definition (livre [France])
The livre is a traditional unit of weight in French speaking countries and in Greece. The livre corresponds to the English pound and to the Spanish libra. The livre is divided into 2 marcs or into 16 onces. The French livre varied from market to market, but the official standard from about 1350 to the introduction of the metric system was the livre poids de marc or livre de Paris of 489.5 grams (1.079 English pounds). In modern France, the livre is used as an informal metric unit equal to exactly 500 grams or 0.5 kilogram (1.1023 pounds). The traditional Greek livre is also about 500 grams.

Unit Definition (slinch)
The slinch is a unit of mass invented by the U.S. National Aeronautics and Space Administration (NASA). The unit is part of a system based on the pound of force and the inch. One slinch is the mass accelerated at one inch per second per second by a force of one pound; thus the slinch equals exactly 12 slugs or about 386.088 pounds (175.1268 kilograms). The word is a contraction of slug-inch. In the U.S. military aircraft industry, this unit is sometimes called a mug. It has also been called a snail.