Two small indentical discs, each of mass m, lie
on a smooth horizontal plane. The discs are interconnected by a light
non-deformed spring of length l0 and stiffness k. At a certain moment one of
the discs is set in motion in a horizontal direction perpendicular to the
spring with velocity v0. Find the maximum elongation of the spring in the
process of motion if it is known to be considerably less than unity.
