Suppose you have two masses, one of 300 g and the other of 400 g, connected to each other by a spring with a spring constant of 3.0 N/m. The masses are attached to walls via springs having a spring constant of 20 N/m. Initially, the 300 g mass is displaced 10 cm to the right and released, while the 400 g mass is at rest at the equilibrium position. Assuming no friction, how long will it take for the 300 g mass to stop moving and for the 400 g mass to start moving?