# What does the rocket ship push off of in order to change its velocity?

May 4, 2016

A rocket ship pushes off of gas expelled from the engine.

#### Explanation:

Key Concepts:

In short, A rocket ship pushes off of gas expelled from the engine.

Motion in a total vacuum with no influences is determined by Newton's Third Law of Motion.

Using this law scientists have determined that ${m}_{g}$${v}_{g}$ = ${m}_{r}$${v}_{r}$ (r being rocket and g being gas)

So when the gas weighs 1g and is moving 10m/s and the mass of the rocket is 1g, the rocket must move 10m/s.

Side Concepts:

Motion in space is not as simple as ${m}_{g}$${v}_{g}$ = ${m}_{r}$${v}_{r}$, though because of several factors: Mass, gravity, drag, and thrust are the main affects on a rocket. If you wish to know more on this subject, ask another question or read Tsiolkovsky rocket equations.

Thrust for rockets are (typically) by RCS thrust, SAS thrust, and main engine thrust.