posted on Jun, 19 2017 @ 10:15 PM
Newton's 3rd law has been experimented over and over for over 200 years.....it's a fact.
College and High School students do experiments that show how the 3rd law works....and work it does.
Take a balloon, fill it with air, then let go and watch it fly...because the compressed gas is escaping out at high velocity (we call this Thrust and
But it's pushing on air! I can hear that being claimed now.
No problem: place balloon in a vacuum chamber and do the same thing. Watch it fly around....no air to push on needed.
Place a small model rocket in that same chamber and light off the engine: watch it fly...again, no air or anything else needed to push it..
But my rocket in space has a mass of 10 tons!
In space, other than gravity, you normally do not have any other force acting upon the rocket. If the rocket is just sitting there, not moving, the
only thing the rocket engine needs to over come is the rocket's inertia.
The impulse from a rocket engine just has to over come the inertia of the rocket....and it will move. If the rocket is already moving, and you want to
change direction, then that inertia will be a LOT more than if it's just sitting there. If the rocket fires and adds it's force in the same direction
that the rocket is already moving, that inertia will be a lot less.
Ion Drives are a perfect example of Newton's 3rd law. All that is coming out of the rocket's exhaust port is charged particles......but because they
are leaving the rocket at a high rate......the space craft will move in the opposite direction. Slowly at first....ion drives have a very, very small
impulse....but the craft will move.
So what would be a rocket's top speed then?
Easy: it's top speed will be that of the exhaust velocity....but only if you have enough fuel for the rocket to reach that speed. Once a rocket's
forward velocity equals that of the exhaust velocity, it can go no faster (assuming you're in a vacuum with no opposing force to that motion).