Added mass fluid quasi-momentum. Unsteady forces due to a change of the relative velocity of a body submerged in a fluid can be divided into two parts: the virtual mass effect and the Basset force. The origin of the force is that the fluid will gain kinetic energy at the expense of the work done by an accelerating submerged body. It can be shown that the virtual mass force, for a spherical particle submerged in an inviscid, incompressible fluid is where bold symbols denote vectors, formula_2 is the fluid flow velocity, formula_3 is the spherical particle velocity, formula_4 is the mass density
Body mass index depends upon weight and the "square" of height. Since mass increases to the "3rd power" of linear dimensions, taller individuals with exactly the same body shape and relative composition have a larger BMI. The mathematician Prof Nick Trefethen, who observed this said, “BMI divides the weight by too large a number for short people and too small a number for tall people. So short people are misled into thinking that they are thinner than they are, and tall people are misled into thinking they are fatter.” For US adults, exponent estimates range from 1.92 to 1.96 for males and from