what is horsepower? how do you determine it? why is it called horsepower? can someone please just explain horsepower in general to me i’m so confused why doesn’t it have anything to do with horses? ):
In: Engineering
In physics power can be defined as force applied to an object over a distance during a specific time or P = F * (D/T).
For example, if you were pushing a box down a hallway and it took you 10 minutes, we could define how much power you used based on how much force you had to apply to move the box and how long the hallway was (since we already know the time).
Prior to the invention of motors, animals were the primary source of a lot of power (other than humans). Mules might turn a grinding wheel, oxen might pull a plow, horses would pull a cart, etc. When people started selling motors it made sense to compare it to a commonly used animal and for a lot of the tasks the engines were being used the main animal was the horse. Of course every horse is different, so a sort of average or common value was created to represent a standard horse.
James Watt (whom the unit Watt is named after) performed experiments to measure how much power a horse could generate to try to come up with this unit. After experimenting they set the value to be 33,000 foot-pounds (44,742 J) per minute which is about 746 Watts (the metric unit of power), this is the imperial horsepower value. There is a separate metric horsepower value of 735.5 Watts as well, just to make things confusing.
Watt’s original experiment for measuring horsepower was based on how many times a horse could turn a mill wheel in one hour. The later standardized definition based on that experiment was the power required to lift 550 lbs by 1 foot in one second. The metric horsepower was then defined as the power required to lift 75 kg by 1 meter in 1 second.
To measure horsepower today there are various methods and equipment, but they would all be calibrated to the known imperial and/or metric standard.
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