consider this combination as a single effective spring. if one spring stretches a distance dL when pulled by the force T, how much would this combined spring stretch when pulled by the same force T

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.