Tropic of Cancer (0.468″) of latitude, or 15 metres, per year (it was at exactly 23° 27′N in 1917 and will be at 23° 26'N in 2045). See axial tilt and circles of latitude for further information. North of the tropic are the subtropics and the North Temperate Zone. The equivalent line of latitude south of the Equator is called the Tropic of Capricorn, and the region between the two, centered on the Equator, is the tropics. There are approximately 13 hours, 35 minutes of daylight during the summer solstice. During the winter solstice, there are 10 hours, 41 minutes of daylight. Starting
Degrees of freedom (physics and chemistry) system is the sum of the average energies associated with each of the degrees of freedom: A degree of freedom is quadratic if the energy terms associated with this degree of freedom can be written as where is a linear combination of other quadratic degrees of freedom. example: if and are two degrees of freedom, and is the associated energy: For example, in Newtonian mechanics, the dynamics of a system of quadratic degrees of freedom are controlled by a set of homogeneous linear differential equations with constant coefficients. are quadratic and independent degrees of freedom if the energy associated with