[organian]

A little nitpick - energy is not momentum squared: Momentum = mv and kinetic energy = 1/2 mv^2 So energy is proportional to mv^2 rather than (mv)^2

[javajosh]

Hey, thanks for that. However, at the end of the day, mass is a constant. A constant squared is still a constant. To wit, for any given system, we can always pick units that make m=1.