In road vehicles the power-to-weight ratio is often used as an indication of likely accelerative performance.

The power to mass classes correspond to the following (rounded to the nearest integer

The largest space nuclear power systems, the Topaz nuclear reactors developed by the former Soviet Union, generated 10 kilowatts and had a specific power, or alpha, of 100 kilograms per kilowatt.

In fact, the largest space nuclear reactor ever built, the Soviet[-era] Topaz, had a power of 10 kilowatts and a power-to-mass ratio of 10 watts per kilogram.

In fact, the largest space nuclear reactor ever built, the Soviet (era) Topaz, had a power of 10 kilowatts and a power-to-mass ratio of 10 watts per kilogram.

In fact, the largest space nuclear reactor ever built, the Soviet (era) Topaz, had a power of 10 kilowatts and a power-to-mass ratio of 10 watts per kilogram.

MAN's impressive engines boast the lowest power-to-weight ratio in their class and a mileage of 1.5 million kilometres with maintenance intervals every 120,000 kilometres.