a 20kg block is connested to a 30kg block by a string that passes over a frictionless pully. the 30kg block is connected to a spring that has niglible mass and a force constant of 250n/m.the 20kg block is pulled 20cm down the incline(40 degrees) and released from rest find the speed of each block when the spring is unstreched

Answer 1

I can't visualize what is going on from your description but, when the spring is unstretched, the potential energy initially stored in the spring will be converted to kinetic energy of both masses and an increase in potential energy of the mass that slides back up the incline.