When a multi-stage booster is fired into space, the mass of the booster changes as the fuel is burned during flight. Discuss how the change in mass influences the acceleration of the booster. When should the first stage of the booster be jettisoned (at maximum velocity, maximum acceleration, maximum altitude, or at some other time)? Justify your selection and give your own example of how mass influences acceleration and describe the process as it happens in your example.