Convert from slug to libra [Portugal, Spain]

Unit Definition (slug)
The slug is a unit of mass in the English foot-pound-second system. One slug is the mass accelerated at 1 foot per second per second by a force of 1 pound. Since the acceleration of gravity (g) in English units is 32.174 04 feet per second per second, the slug is equal to 32.174 04 pounds (14.593 90 kilograms). The slug was formerly used in calculations in mechanics and engineering, but it has been largely abandoned in favor of metric units. The unit was called the "engineer's mass unit" during the late nineteenth century. The British physicist A. M. Worthington first called it a slug in a 1902 textbook. (Probably he had in mind older uses of the word to mean a weight or a projectile. In the 1600's a slug was a roughly shaped lump of metal shot from a primitive cannon.)

Unit Definition (libra [Portugal, Spain])
The libra [Portugal, Spain] a traditional unit of weight. The libra was the Roman unit from which the English pound is descended; the symbol "lb" for the pound comes from this unit. The Spanish and Portuguese units are larger, generally in the range from 1.011 to 1.016 English pound (very close to 460 grams). The Spanish libra equals 16 onzas, and the Portuguese libra equals 16 onças. The word "libra" is sometimes used now for the kilogram, a much larger unit.