Equations of motion force the object exerts. Replacing momentum by mass times velocity, the law is also written more famously as since is a constant in Newtonian mechanics. Newton's second law applies to point-like particles, and to all points in a rigid body. They also apply to each point in a mass continua, like deformable solids or fluids, but the motion of the system must be accounted for, see material derivative. In the case the mass is not constant, it is not sufficient to use the product rule for the time derivative on the mass and velocity, and Newton's second law requires some
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