Two masses m1 and m2 are connected by a massless spring of spring constant k and unstreched length l. The
masses are placed on a frictionless straight channel – which we consider our x-axis. They are initially at rest
at x = 0 and x = l, respectively. At t = 0, a velocity of v0 is suddenly imparted to the first particle. At a later
time t0, the centre of mass of the two masses is