Three infinite horizontal rails are at distance l from each other. Three beads of equal masses m can slide along the rails without friction. The three beads are connected by identical springs of constants k and equilibrium/unstretched length l/2. 1. Find the normal modes and the normal frequencies. 2. At time t = 0 one of the masses is suddenly given a velocity v0. Find how the velocities of all three masses will depend on time. Find how the sum of the three velocities depends on time. Why?