If the cat jumps forward it accelerates away from the skateboard and the only way to do that is for its feet to use that skateboard as its leverage
Well thanks for finally admitting it is the skateboard that matters, not the air.
It can also do this vertically, using the skateboard as its leverage.
which means slowing the skateboard down in order to accelerate itself.
Only if it jumps of forwards. If it jumps of backwards it will accelerate the skateboard as it slows itself.
Then how about explaining how it works with a rocket vertically.
It has already been explained to you repeatedly. You just choose to remain wilfully ignorant.
How about you start explaining why vertically is magically different or why a rocket should do anything like you claim, backing it up with rational arguments and evidence?
Let's build a man sized cardboard rocket, hypothetically.
All it will be will be a tube that can fit me and you in with our feet soles touching, knees bent and our heads touching a closed lid on each side of the tube.
I'll liken this to how your rocket works.
Do you agree with this part?
We would be the fuel under pressure.
If I push into you, you push into me.
Your head goes to the top head and mine goes to the bottom, exhaust.
Am I on the right lines with your rocket?
If I am then I'll carry on. If not, tell me why not.
No, what rocket do you see burning without having the exhaust go out the bottom?
That would be a firecracker.
Try it this way:
Only the top is closed.
He starts up against the top. You start directly below him.
You then push off him.
That results in you being pushed down and him being pushed up. He is contact with the rocket and thus pushes it up as well.
You then fly out the bottom of the tube.
We both start to stretch out but that results in me being pushed out by you using your head against the top of your rocket and me simply having nothing to push against you, so I merely fall out and your head simply uses the rocket top as a leverage to push me out. It does not move your rocket.
Pure bullshit.
Why does it move him in the first instance, but then magically not in the second?
You started off well. You push against each other and you both move.
Remember, action and reaction?
It doesn't matter who pushes who as every action has an equal and opposite reaction.
I resisted by having something outside to push into
You resist by existing. You don't need a magical atmosphere to resist against you, unless you want to claim you can accelerate objects with no force required if the atmosphere isn't there.
If the latter then the rocket doesn't need a force to accelerate.
You see, if I don't have something to resist my push against your push then your push is pointless.
Can you see what I'm saying?
Yes, we all see what you are saying. You are baselessly spouting crap which isn't backed up by any evidence at all.
Stop just baselessly asserting garbage.
We also see you running off on another pathetic distraction.
The question you were trying to respond to wasn't why doesn't it work in space, it is why doesn't it work vertically.
It makes no sense.
No, the crap you are spouting makes no sense.
You are yet to show an issue with real physics. Instead all you have are your repeated lies, which aren't even consistent.
It's all about displacing an amount of atmospheric pressure by pushing the object against it to create an opposite effect.
If that was the case the object would move while being pushed and then stop dead.
Once you stop pushing it doesn't magically stop displacing the atmosphere. So by your reasoning, with displacing the atmosphere being the only reason it needs a force, then it still needs that force to continue moving and thus once it leaves your hand or whatever and the force is not applied, it should stop dead.
But does that happen in reality? NO!
Instead it continues moving, only gradually slowing down.
This shows that while the air will result in some resistance, it doesn't provide all of it. It is the object itself resisting motion that provides the resistance.
Have you ever tried to cycle against the wind?
Yes, it is only marginally harder that cycling in still air, which is slightly harder than riding with the wind.
This shows that while the atmosphere does offer some resistance, it is not the main contributing factor.
All you're doing is creating that same effect by compression of your push against atmosphere.