Engine Burnout
In this phase, the rocket expends the entirety of its fuel reserves. This is the phase where the rocket is accelerating, picking up velocity for the entire duration of the burnout. The rocket is moving its fastest at the end of the rocket burnout. This burnout phase is where Newton's Second Law of Motion can really be seen at work. Newton's Second Law of Motion states that a force applied on a mass will cause the mass to accelerate. In mathematical form, this can be seen in the equation that follows.
F=ma
The measurement that best fits the Burnout Phase is the measurement of Impulse. The definition of Impulse is a force applied over a time. The force in this statement is the rocket's thrust, and the time is just the length of the burn. The equation for impulse is as follows:
Impulse can also be thought of as the change in
momentum. In this case, the formula changes. Thinking in
terms of momentum, the equation for impulse is:
J = dp/dt
This formula means the change in
momentum over time, therefore, when looking at a momentum
vs time graph, the slope of the line would be the impulse.