For example, if I took a butane lighter & fired it up, there’s no force in any direction. How does a rocket ignition work & propel itself upwards?
Thanks,
In: Engineering
Stand on a very icy flat frozen lake, carrying something heavy. Throw the heavy thing. You will feel yourself being slid back a bit and your feet will slide back a bit. The harder you can throw it the more you will be flung back. Most of the time we subconsciously plant our feet hard when throwing something, so we don’t notice this effect. But do it somewhere where you have really low friction, like on ice, and you can’t plant your feet hard, then you notice it.
If ice isn’t available, then try floating in a still lake on a rowboat and doing it. take along a supply of rocks, get the boat perfectly still as best you can, and then start throwing the rocks in one direction. You will feel yourself get pushed back the other way (probably rotating the boat a bit as you throw.)
This is also the reason that firing a gun makes the gun kick back. Throw the bullet fast one way, and that pushes the gun back the opposite way.
The hot gasses coming out the back of a rocket is like those thrown rocks or the bullet of a gun. You’re throwing mass one way, causing the platform you’re throwing it from (the rocket) to get shoved the opposite way. The faster you can throw the mass, the more push you will get in the opposite direction for doing so.
The only purpose behind the fiery hotness of the gasses coming out of the rocket is that making a controlled explosion that is constrained in all directions but one is the best way we know of to accelerate a thing up to a high speed very fast. The high speed at which the fuel gets flung is the ends. Exploding the fuel is just the means to that ends.
Latest Answers