The virial theorem states that the total kinetic energy of the objects in a
spherical, self-gravitating, stable assembly is equal to negative 1/2 times the total gravitational potential energy, if the objects can be assumed to have equal masses.
... 41.5% have children under the age of 18 living with them, 70.9% are married couples living together, 7.3% have a female householder with no husband present, and 17.9% are ...