A block of mass 2 kg is attached to a horizontal spring of force constant 130 N/m and to a spring of negligible mass. The string runs over a massless, frictionless pulley to a hanging block off mass 2 kg. Initially the entire system is at rest and the spring is unstretched.
If the 2 kg mass slides on a horizontal frictionless surface, what is the speed of the mass 4 kg when it has fallen a distance 0.4 m downward from its rest poisiton?