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A human in a sprint has approximately 3 kJ of kinetic energy, [20] while a cheetah in a 122 km/h (76 mph) sprint has approximately 20 kJ. [21] One watt-hour, of electricity or any other form of energy, is 3.6 kJ. megajoule The megajoule is approximately the kinetic energy of a one megagram (tonne) vehicle moving at 161 km/h (100 mph).
A kilowatt-hour (unit symbol: kW⋅h or kW h; commonly written as kWh) is a non-SI unit of energy equal to 3.6 megajoules (MJ) in SI units, which is the energy delivered by one kilowatt of power for one hour. Kilowatt-hours are a common billing unit for electrical energy supplied by electric utilities.
A unit of electrical energy, particularly for utility bills, is the kilowatt-hour (kWh); [3] one kilowatt-hour is equivalent to 3.6 megajoules. Electricity usage is often given in units of kilowatt-hours per year or other periods. [4] This is a measurement of average power consumption, meaning the average rate at which energy is transferred ...
In general, proteins have lower energy densities (≈16 kJ/g) than carbohydrates (≈17 kJ/g), whereas fats provide much higher energy densities (≈38 kJ/g), [8] 2 + 1 ⁄ 4 times as much energy. Fats contain more carbon-carbon and carbon-hydrogen bonds than carbohydrates or proteins, yielding higher energy density. [ 9 ]
For example, when a light bulb with a power rating of 100 W is turned on for one hour, the energy used is 100 watt hours (W·h), 0.1 kilowatt hour, or 360 kJ. This same amount of energy would light a 40-watt bulb for 2.5 hours, or a 50-watt bulb for 2 hours.
The following unit conversions may be helpful when considering the data in the tables: 3.6 MJ = 1 kW⋅h ≈ 1.34 hp⋅h. Since 1 J = 10 −6 MJ and 1 m 3 = 10 3 L, divide joule/m 3 by 10 9 to get MJ/L = GJ/m 3. Divide MJ/L by 3.6 to get kW⋅h/L.
Energy; system unit code (alternative) symbol or abbrev. notes sample default conversion combinations SI: yottajoule: YJ YJ 1.0 YJ (2.8 × 10 17 kWh) zettajoule: ZJ ZJ 1.0 ZJ (2.8 × 10 14 kWh)
1 Formula. 2 References. ... [kW] ˙ is the mass rate [kg/s] is the specific heat capacity [kJ/kg K] is the temperature change [K] References. This ...