Motion of a sand-filled funnel: An experiment and model

An experiment is described in which a system consisting of a funnel filled with sand is accelerated. As the sand drains from the funnel, the mass of the funnel and the external forces on the funnel change as the funnel moves, thus achieving nonuniform acceleration. Additionally, a spreadsheet is described that models the velocity time behavior of the system. Good correlation between experiment and theory can be easily achieved.