For 10 points, name this physical quantity which is conserved in closed, isolated systems, commonly defined as the product of mass and the velocity.
In translational motion, Noether's Theorem states that invariance of physical systems leads to its common treatment in classical mechanics. For objects without rest mass, it is given as energy over the speed of light or Planck's constant over wavelength. In quantum mechanics, it is a conjugate variable with position, and in classical mechanics, its change is given as the time integral of force, also known as impulse. For 10 points, name this physical quantity which is conserved in closed, isolated systems, commonly defined as the product of mass and the velocity.
In translational motion, Noether's Theorem states that invariance of physical systems leads to its common treatment in classical mechanics.
{linear momentum} [prompt on momentum; do not accept “angular momentum”]