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Power in mechanical systems is the combination of forces and movement. In particular, power is the product of a force on an object and the object's velocity, or the product of a torque on a shaft and the shaft's angular velocity. Mechanical power is also described as the time derivative of work.
eco: average power consumption per person in the United States in 2008 (87,216 kWh/year) 1.4 × 10 4 W tech: average power consumption of an electric car on EPA's Highway test schedule [25] [26] 1.45 × 10 4 W astro: power per square metre received from the Sun at Mercury's orbit at perihelion: 1.6–3.2 × 10 4 W
The term RMS power is sometimes erroneously used (e.g., in the audio industry) as a synonym for mean power or average power (it is proportional to the square of the RMS voltage or RMS current in a resistive load). For a discussion of audio power measurements and their shortcomings, see Audio power.
A power rating can also involve average and maximum power, which may vary depending on the kind of equipment and its application. Power rating limits are usually set as a guideline by the manufacturers, protecting the equipment, and simplifying the design of larger systems, by providing a level of operation under which the equipment will not be ...
The average steam consumption of those engines (per output horsepower) was determined to be the evaporation of 30 pounds (14 kg) of water per hour, based on feed water at 100 °F (38 °C), and saturated steam generated at 70 psi (480 kPa). This original definition is equivalent to a boiler heat output of 33,485 Btu/h (9.813 kW).
More commonly used is the power spectral density (PSD, or simply power spectrum), which applies to signals existing over all time, or over a time period large enough (especially in relation to the duration of a measurement) that it could as well have been over an infinite time interval. The PSD then refers to the spectral energy distribution ...
The portion of instantaneous power that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as instantaneous active power, and its time average is known as active power or real power.
Peak power refers to the maximum of the instantaneous power waveform, which, for a sine wave, is always twice the average power. [16] [1] [17] [18] For other waveforms, the relationship between peak power and average power is the peak-to-average power ratio (PAPR).