Convert kilojoule to Foot-pound

The calorie of food labels is really the kilocalorie: 1 kcal = 1,000 cal = 4.1868 kJ, the heat that warms a kilogram of water by one degree. Nutrition labels in the EU must give both kJ and kcal, the US gives 'Calories' with a capital C meaning kcal, and the adult reference intake is 2,000 kcal, about 8,400 kJ. A slice of bread is around 80 kcal, an hour's brisk walk burns about 300.

The foot-pound is the work of a one-pound force over one foot, 1.356 J. It is used in the US for the muzzle energy of firearms and airguns (a .22 rifle delivers about 100 ft·lb, a hunting rifle 2,000–3,000) and for the impact energy of tools and hammers. Do not confuse it with the pound-foot of torque: the same product of force and distance, but nothing moves, so it is not energy.