Problem 1.148

The reference frame, in which the centre of inertia of a given system of particles is at rest, translates with a velocity V relative to an inertial reference frame $K .$ The mass of the system of particles equals $m$, and the total energy of the system in the frame of the centre of inertia is equal to $\widetilde{E}$. Find the total energy $E$ of this system of particles in the reference frame $K$