Deriving relativistic momentum and energy

We present a new derivation of the expressions for momentum and energy of a relativistic particle. Contrary to the procedures commonly adopted in textbooks, the one suggested here requires only the knowledge of the composition law for velocities along one spatial dimension and does not make use of the concept of relativistic mass. The basic ideas are very general and can be applied also to kinematics different from the Newtonian and Einstein ones, in order to construct the corresponding dynamics. PACS: 03.30.+p; 01.40.-d; 01.55.+b