Hour - Derived Measures and Applications

Derived Measures and Applications

Although the SI unit for speed is meters per second, in everyday usage kilometres per hour or, in the USA and the UK, miles per hour are more practical. Occasionally the metre per hour is used for slow-moving objects like snails.

Worker compensation is commonly based on working time in terms of number of hours worked, referred to as an hourly wage. Worker schedules are categorized by number of work hours per day or number of work hours per week; these are regulated and distinguish part-time from full-time jobs. The man-hour describes the amount of work that a person can complete in one hour. Many professionals such as lawyers and therapists charge a fee per hour.

The credit hour measures the time commitment of an academic course (typically university level) in terms of "contact hours" between students and staff per week. For example, a class that meets for one hour three times a week is said to be a 3-hour class.

The kilowatt hour, the energy expended by a 1000 watt device in one hour, is commonly used as a billing unit for energy delivered to consumers by electric utilities. Conversely, the Btu per hour is a unit of power used in the power industry and heating/cooling applications. In the railroad industry, when sharing locomotives, the horsepower-hour may be used as a measure of energy.

The ampere-hour is a unit of electric charge used in measurements of electrochemical systems such as electroplating and batteries.

In indoor air quality, air changes per hour measures how many times the air within a defined space, such as a room or house, is replaced in an hour.

Passengers per hour per direction is used to describe the capacity of public transport systems.

Pound per hour is a mass flow unit used for fuel flow in engines.