Irodov Problem 1.149

The velocity of the center of mass of the two discs is given by,

.


The total energy of the system will be conserved. Initially there is no extension in the spring and thus the total energy is equal to the kinetic energy in the discs. The kinetic energy of the system at the initial time instant as seen from the CG is given by,







But since v1 and v2 are perpendicular,