**I cheated and found this through an internet search.** :lol:

HORSEPOWER

Horsepower is a measure of the work an engine can do. The word "horsepower" was coined by James Watt, an engineer from Scotland who compared the work of his invention, the steam engine, to that of a horse. Watt wanted to know how many horses his steam engine would replace. He found that a robust horse could lift a 150-pound weight 220 feet in the air (using a pulley system) in 60 seconds. This measurement of work became the standard we still use today. More precisely, horsepower is the force needed to move a specific amount of weight a specific distance in a specific amount of time. Two key words come into play here: "work" and "power." Work is the amount of force than can be applied over a specific distance (WORK = FORCE x DISTANCE). Power is a measurement of the time it takes to accomplish the work. An understanding of the word "horsepower" hinges on grasping the literal meaning of these two words.

Visualize a man pushing his 4x4 off the trail after completely torching his overburdened alternator. The man has to push his 6,000-pound truck on 44-inch Gumbo Monster Mudders (force) 15 feet (distance) to get it off the road. If the man succeeds all by himself, he will have accomplished 9,000 lb-ft of work. On the other hand, he won't have done any work, no matter how hard he tries, if the truck doesn't budge. The only thing that would make his job easier is if he had the power to push his rig off the trial in 10 seconds rather than 30 seconds. More physical power, in combination with his work effort, is needed move the truck more quickly. Whether he moves the truck in 10 seconds or 30 seconds, the man will have done the same amount of work.

HORSEPOWER = TORQUE x RPM/5,252

TORQUE

Think "twisting force" when you consider the word torque. It differs from "work" in that torque is a measure of force that produces rotation or twisting action around an axis. In essence, torque is twisting force. Torque is the product of the force, measured in pounds, and a radius perpendicular to the axis of the force extending to the point where the force originates, measured in feet. This resulting figure is expressed in pounds-feet, or lb-ft. As an object rotates around a given point (the axis), the speed of its rotation depends on both the applied force (the twisting force) and the torque arm (or moment arm). The torque arm represents the distance from the point of rotation to the point where the force is applied. Torque, then, is the product of the force and the torque arm.

You apply torque every time you affix a wrench to the head of a bolt and turn it. When you place that wrench on a bolt head, you're going to hang onto the wrench handle with all 200 pounds of your body weight. If the wrench is two feet (the wrench handle acts as the torque arm) in length, the mathematical expression would be: 2(distance) x 200 pounds (force applied) = 400 lb-ft (torque). Another way to look at it is to visualize a rope wrapped around a drum with a 1-foot radius. If the rope were to be pulled with 550 pounds of force, the torque would equal 550 lb-ft.

TOQUE = DISTANCE x WEIGHT