Search results
Results From The WOW.Com Content Network
The kinetic energy of a 2 kg mass travelling at 1 m/s, or a 1 kg mass travelling at 1.41 m/s. The energy required to lift an apple up 1 m, assuming the apple has a mass of 101.97 g. The heat required to raise the temperature of 0.239 g of water from 0 °C to 1 °C. [15] The kinetic energy of a 50 kg human moving very slowly (0.2 m/s or 0.72 km/h).
In the SI system (expressing the ratio E / m in joules per kilogram using the value of c in metres per second): [35] E / m = c 2 = (299 792 458 m/s) 2 = 89 875 517 873 681 764 J/kg (≈ 9.0 × 10 16 joules per kilogram). So the energy equivalent of one kilogram of mass is 89.9 petajoules; 25.0 billion kilowatt-hours (≈ 25,000 ...
The joule-second also appears in quantum mechanics within the definition of the Planck constant. [2] Angular momentum is the product of an object's moment of inertia, in units of kg⋅m 2 and its angular velocity in units of rad⋅s −1. This product of moment of inertia and angular velocity yields kg⋅m 2 ⋅s −1 or the joule-second.
The SI unit for specific energy is the joule per kilogram (J/kg). Other units still in use worldwide in some contexts are the kilocalorie per gram (Cal/g or kcal/g), mostly in food-related topics, and watt-hours per kilogram (W⋅h/kg) in the field of batteries.
Energy is defined via work, so the SI unit of energy is the same as the unit of work – the joule (J), named in honour of James Prescott Joule [1] and his experiments on the mechanical equivalent of heat. In slightly more fundamental terms, 1 joule is equal to 1 newton metre and, in terms of SI base units
"The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 10 −34 when expressed in the unit J s , which is equal to kg m 2 s −1 , where the metre and the second are defined in terms of c and ∆ ν Cs ."
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m 2 ⋅s −3. [1] [2] [3] It is used to quantify the rate of energy transfer.
The dimension of power is energy divided by time. In the International System of Units (SI), the unit of power is the watt (W), which is equal to one joule per second. Other common and traditional measures are horsepower (hp), comparing to the power of a horse; one mechanical horsepower equals about 745.7 watts.