translational kinetic energy

is: the energy that a body has by virtue of the motion of its centre of mass. [P2.4]

is given: by or equivalently by where the mass of the body is and its speed is [P2.5]

is: for a collection of bodies (or particles), the sum of the individual translational kinetic energies. [P2.4]

is conserved: in elastic collisions. [P2.4]