What is horsepower and what is it equal to

Despite the fact that such a unit of measure as horsepower is not officially included in the International System of Units, it is often used in the modern world. Not a single description of a car is complete without mentioning its power, expressed in horsepower. Moreover, these indicators are based on the calculation of transport tax or insurance premiums in our country. At the same time, the international organization that determines the order in the field of metrology generally called for the abandonment of the use of such a concept as horsepower, and recommended that it be disposed of as soon as possible in the modern world. What kind of power is this, and what does it mean?

The recommendations of the international commission are in principle justified, given the fact that the world has developed an ambiguous situation with the use of this term: one horsepower in different countries is equivalent to different power indicators. This situation causes confusion and leads to inconvenience in those areas where this indicator is used, and this is primarily the automotive industry.

The term itself was coined by James Watt, a famous scientist who lived in Scotland. His scientific activity was related to steam engines, which thanks to him were improved and served as an impetus for economic development. Since horses have long been the main driving force of human civilization, it is not surprising that when James Watt needed to characterize the work of his new steam engines, he chose a workhorse as an indicator of power. The scientist measured what maximum load 1 horse can move at a speed of 1 m / s. It turned out that such a burden should weigh 75 kilograms, and horsepower will be equivalent to 735.5 watts.

But at the end of the XIX century, the unit of power received the official name of watts - in honor of the outstanding scientist who did so much to promote steam engines. But such a seemingly archaic value as horsepower is still alive and, it seems, is not going to disappear for the sake of more progressive watts and international metrological commissions.