This model illustrates the law of conservation of momentum using jet propulsion as an example. The graph displays the change in rocket speed over time. The relative speed u of gas ejection from the rocket is assumed to be constant. Modify the mass Mf of the fuel in the rocket and watch the rocket?s acceleration until the fuel completely burns out. Note that after no more fuel is left, the rocket starts moving with a constant velocity. Try to determine what ratio of the initial and of the final masses M0/M is required for the rocket to reach orbital velocity (at the given propulsion speed). Check your result using the Tsyolkovsky formula.