Search results
Results from the WOW.Com Content Network
The tonne (t) is an SI-compatible unit of mass equal to a megagram (Mg), or 10 3 kg. The unit is in common use for masses above about 10 3 kg and is often used with SI prefixes. For example, a gigagram ( Gg ) or 10 9 g is 10 3 tonnes, commonly called a kilotonne .
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 Δν Cs. —
The siriometer is an obsolete astronomical measure equal to one million astronomical units, i.e., one million times the average distance between the Sun and Earth. [13] This distance is equal to about 15.8 light-years, 149.6 Pm, or 4.8 parsecs, and is about twice the distance from Earth to the star Sirius. [14]
The gram (originally gramme; [1] SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one thousandth of a kilogram.. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre [1 cm 3], and at the temperature of melting ice", [2] the defining temperature (≈0 °C) was later changed to 4 ...
The Planck energy E P is approximately equal to the energy released in the combustion of the fuel in an automobile fuel tank (57.2 L at 34.2 MJ/L of chemical energy). The ultra-high-energy cosmic ray observed in 1991 had a measured energy of about 50 J, equivalent to about 2.5 × 10 −8 E P .
A 5 kg mass of 239 Pu contains about 12.5 × 10 24 atoms. With a half-life of 24,100 years, about 11.5 × 10 12 of its atoms decay each second by emitting a 5.157 MeV alpha particle. This amounts to 9.68 watts of power.