Myth: 1 G barrel rolls are impossible.

I used the escape velocity limitation to disallow the obvious
argument.


The intitial velocity limitation says 'vertical'. I don't care what
size the 'walnut' is, it will be impacted given there was no
horizontal velocity component.

Even if there was, by the way, the Newtonian physics demand the path
will cross the starting point, and the implication to most readers
would be that was on a surface.

Jose, I don't think from an initial impluse, which is the model I
described, you can avoid impact unless the mass of the projectile is
such that conservation of momentum would demand the launching surface
move enough out of the way of the way to avoid the impact.

You really can't go orbital with a initial impulse launch from a
realizable surface unless the object gets redirected as it gains
altitude. I did not allow that redirection in my model.

As for abstract thinking mentioned in another post? I might use a word
other than abstract.