Heat is a form of energy, and in the 51 system energy has units of joules (J). (Recall that one joule is equal to one newton times 1 meter, or 1 J - 1 Him.) We will typically use unim of joules when measuring heat and intemal energy. Some other units are commonly used to measure heat. A calorie (cal) Is defined as the amount of heat required to raise one gram of pure water (at 1 atmosphere of pressure} by 1 degree Celsius. The conversion between calories and joules is 1 cal I 4.136 J. Be careful; there are actually two different units commonly called 'calorle." You may have seen on food packages the number of \"calories' the food contains (a measurement of the amount of energy the food releases upon combustion). The "calories" listed on food are not the 'calories" described abovethey are actually "food calories' (sometimes called 'Calories," with a capital 'C," and abbreviated Cal). A 'food calorie" Is equal to 1,000 calories, or 1 kilocalorle. The label of a 12 ounce can of soda states it \"contains" 170 food calories (meaning 170 food calories are released when it is fully metabolized}. How many ordinary calories Is this equivalent to? How many joules is this equivalent to? J H Finally, another unit of heat that you may encounter is the BTU (short for "British thermal unit\"), which Is used in some industrial and engineering applications in the United States. It is equal to about 1,055 J. Air conditioners and heating units In the United States are often rated in \"BTUs', but note that this rating is really the amount of heat the unit can transfer In one hour. So, In these cases, it's really a measurement of power, where 1 BTU (per hour} is about 0.293 watts. A certain household furnace is rated to produce 100,000 BTU per hour. What is the power output of the furnace in units of watts? W H