A block of mass \(m\) is attached to an ideal horizontal spring of force constant \(k\) and oscillates on a frictionless surface with total mechanical energy \(E_0\). The system's velocity \(v\) as a function of position \(x\) is plotted over a complete cycle. The experiment is repeated using an identical spring and an oscillator of mass \(2m\), also with total mechanical energy \(E_0\). Which of the following graphs best represents the velocity \(v\) versus position \(x\) for the system of mass \(m\) (solid curve) and the system of mass \(2m\) (dashed curve)?