A cart of mass \(M_c\) on a frictionless horizontal surface is connected by an ideal string passing over a massless, frictionless pulley to a hanging block of mass \(m_h\). A student measures the magnitude of the system acceleration \(a\) as a function of the parameter \(f = \dfrac{m_h}{M_0}\) under two different experimental procedures:

Procedure 1: The total mass of the system is held constant at \(M_0\) such that \(M_c + m_h = M_0\), and mass is transferred from the cart to the hanging block to increase \(f\) from \(0\) to \(1\).

Procedure 2: The mass of the cart is held constant at \(M_c = M_0\), and mass is added exclusively to the hanging block to increase \(f\) from \(0\) to \(1\).

Which of the following graphs best represents the acceleration \(a\) as a function of \(f\) for Procedure 1 (solid line) and Procedure 2 (dashed line)?