1. I have launched model rockets and watched them continue to fly up after the engine burns out, so I know that Scepti is wrong from personal observations. (I’ve also tossed many balls into the air. Try it—it’s fun!)
Given everything he's said about acceleration I sincerely doubt that qualifies as an argument.
2. I have taken physics classes where we learned that f=ma is an algebraic formula and not just a general relationship. Each of the terms (force, mass, acceleration, velocity, momentum, speed...) have specific meanings and specific ways that they interact with each other that has been known and studied for hundreds of years. Now Scepti thinks he can just scrap all that? Our entire advanced technological society is built on Newton’s Three Laws. The entire aerospace industry has it wrong? Trains, planes, and automobiles work by some new set of rules that Scepti just popped out last month? Not a chance.
Is not an actual argument, at best a handwave
3. If Scepti doesn’t even know the meanings of the most basic scientific terms, can’t understand the easiest scientific equation around, and doesn’t seem to know that people can (or how they can) throw balls in the air, then how in the great, big, beautiful, round world is he going to come up with cutting-edge physics?!
Just a general mess.
There are arguments to be made but first you need to actually pay attention to what the other person is saying.
This is kind of related to the first question as far as trying to maintain a constant velocity goes. For a kind of illustration, if an object is travelling at some fast, constant velocity of 100m/s and then has its power cut off it would immediately drop to 0m/s. But then if there was a tiny boost in the engines for a split second and it travelled at 100m/s with an acceleration of 1m/s/s at the instant the engines were cut off, would it just decelerate to lose that 1m/s/s, or would it lose that and then decelerate through the 100m/s?
I am far too tired right now so there is a chance that made no sense at all. Apologies if so.
You seem to be suggesting a two stage rocket if I'm reading you correctly.
Let's assume you are.
Ok the rocket shuts down its first burn and jettisons its structural mass for that particular burn, it would cease to advance vertically up from that immediate burn out at constant velocity.
As it's shedding its mass it would immediately start to fall before any next burn can kick in, which would render the rocket a mess and basically an impossible happening.
However, I'm talking about the so called space rocket fantasy as we are shown it, so let's get back to what we do see.
What you really see in a two stage rocket (model) is a springboard acceleration to deceleration and then a separation and then a reburn.
If this happens fast then the rocket can still be decelerating (moving up) as the next stage kicks in and immediately kick in another springboard effect until it reaches constant velocity.
So what I'm basically saying is, you will never get a stage separation and reigniting booster on any rocket moving at constant velocity.
I'm not entirely sure if I've answered your query but if not feel free to try and get me to clarify.
I'm not too focused on applying it yet, I'm intentionally trying to keep out of the rocket side of things until I understand the underlying principles of what you're saying. I'm just trying to gauge how significant this 'dead stop' effect would be in other situations.
Like, if we go back to the platform on a rope attached to a lift, if the lift goes up at a constant velocity (say, 10m/s, let's make it absurdly fast) and cuts the rope, the platform comes to a dead stop. If the lift is accelerating up, then the platform would decelerate.
But what if we try to take the middle ground between those two situations? The lift travels at a constant speed, then accelerates say 1cm/s for a second as the rope's cut, or for half a second as the rope's cut.
Or for that matter, if the lift decelerates by 1cm/s as the rope's being cut, thus still meaning the platform does not have a constant speed (slack in the rope aside. Worst case replace that with a rigid iron pole that gets unscrewed and let go).
How much/how long for would the platform decelerate normally in those cases?
The options I can see would be the object decelerating to 0m/s but much faster than if it had been accelerating for longer, the object decelerating normally to 0m/s with no difference to regular behaviour, or the object decelerating to its constat velocity and then reaching a dead stop (though that seems odd with the potential deceleration to prevent constant velocity case).
I don't quite understand the physics at play in your rocket illustration so I can't completely read it. I think you're saying the middle case, the problem is just with the practicalities of creating such a system with respect to a rocket, but i'm not sure.