An experiment is designed to determine the unknown mass \(M\) of a projectile that moves along a frictionless horizontal track. In each trial, the projectile travels at initial speed \(v_i\), strikes a fixed barrier, and rebounds in the opposite direction at speed \(v_f\). A sensor on the barrier measures the contact force \(F(t)\) over the collision duration \(\Delta t\), and software computes the magnitude of the impulse \(J = \int_0^{\Delta t} F(t)\,dt\). Which of the following pairs of quantities, when plotted on the vertical and horizontal axes, will produce a linear graph whose best-fit slope is directly equal to \(M\)?