# This is how you measure horsepower

With two rotating rollers, a measuring device and a computer, you can calculate how many horsepower an engine in a car has.

With two rotating rollers, a measuring device and a computer, you can calculate how many horsepower an engine in a car has.

## The two rollers rotate and can measure the horsepower with increased resistance.

The power in a car engine is measured by a special horsepower meter – a device with two metal rollers where the tires of the car are made to rotate.

As the tires rotate, the rollers also do so at the same speed.

The rotation is detected by a measuring device – a so-called dynotester – which records the rotation speed of the tires and revolutions per minute.

The information is used by a computer to calculate the horsepower of the engine based on an equation and thus find out the power of the respective engine.

#### The family car gets rear wheels

An engine in a family car usually has around 150 horsepower, but in smaller cars the number can be around 75 horsepower. However, these cars pale in comparison to the Formula 1 racing cars that boast more than 1,000 horsepower engines.

The difference between the family car and the racing car becomes even greater because racing cars have much more power compared to their weight. If the family car was to be as fast, its engine would have to have 1,800 horsepower.

#### A horse is stronger than one horsepower

One horsepower corresponds to about 736 watts – or the effort needed to lift a 75 kg mass, one meter vertically up from the earth’s surface in about one second.

Despite the name of the unit of measurement, one horsepower does not correspond to the power of one horse. The animal can produce 2.5 – 10 horsepower.