Posted on 12/29/2023 12:48:57 PM PST by Red Badger
“The faster an object goes, the more fuel it needs to go faster”
Force = Mass x Acceleration. Speed is not in the equation. In outer space there is no resistance like gravity or friction (Maybe a little gravity). A continuous force creates a continuous acceleration rate. So if you burn the same rate you accelerate the same rate regardless of the speed. When you are going faster, you in fact cover a greater distance with the same amount of fuel because no fuel is used to overcome friction or gravity.
Fuel burn in rockets is measured in mass over time. As you consume fuel the spaceship looses mass. With a steady burn rate the acceleration rate actually increases as the mass decreases. Once you have reached the desired speed, you can cut the engines and coast indefinitely without slowing down.
“The speed with which the burned fuel is ejected is finite, so the spacecraft cannot go faster than the exhaust.”
Totally wrong.
Thrust is the amount of force NOT SPEED. Rocket engines have pounds of thrust, that is a force. Never heard of speed of thrust. If you indefinitely apply 5 lb. of force on an object in outer space that is beyond any gravity forces, it will keep accelerating, indefinitely.
Force = Mass x Acceleration. Period
“Newton’s Second Law: For every action, there is an equal and opposite reaction.
Blow exhaust out a rocket nozzle at 30,000 MPH (theoretical) and the spacecraft will be propelled to 30,000 MPH, but no more than that.”
PLEASE go back and take your high school physics class again.
That would be NEWTON”S THIRD LAW and it is about FORCE not SPEED.
“in space there is no resistance. so is it safe to assume that as long as the rocket is thrusting, the craft will continue to gain speed?
YES. Until you run out of fuel. Then it will coast at that speed indefinitely
F = M x A.
Your are wrong because this is about achieving the speed of light, not acceleration over ground in a constant environment.
EMC2 is different kettle of fish, where mass is the driving factor. You essentially need infinite fuel to reach the speed of light using chemical means. There is no “cutting the engines”.
According to the theory, mass increases the closer one gets to the speed of light, necessitating more fuel, not less.
Aerospike! Thats what I couldnt remember. So technologically advanced I cant keep up.
PLEASE go back and re-read my post #16 where I corrected myself before you even read this thread.
“Your are wrong because this is about achieving the speed of light, not acceleration over ground in a constant environment.”
I am talking about accelerating in space not over ground. I also did not mention the speed off light and any related boundaries(ie the increase in mass) which may be the reason you can’t get there. Merely correcting all of the wrong statements about the speed of the thrust etc. I talk about cutting engines and coasting as an example that yes the space ship can go faster than the speed of thrust which would be at zero.
PLEASE go back and re-read my post #16 where I corrected myself before you even read this thread.
OK I will only correct the part where Newton’s 3rd law is about force not speed.
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