Myth: 1 G barrel rolls are impossible.

El Maximo writes:

I'm sure there are enough definitions of orbit for you to choose from that
you wouldn't bother learning, only arguing.

In other words, I am not in error.

Well, MX, consider the case of a ballistic track that starts off with
an initial vertical velocity that is less than escape velocity.

Up, then down, until it hits what someone so nicely described as 'the
hard edge of the sky". Is your assertion that is orbital?

Well, MX, consider the case of a ballistic track that starts off with
an initial vertical velocity that is less than escape velocity.

Up, then down, until it hits what someone so nicely described as 'the
hard edge of the sky". Is your assertion that is orbital?

Suppose that, as the rock was passing through the soft part of the sky
(we neglect air friction because this is powered freefall flight), the
earth shrunk to the size of a walnut. The flight path would stay the
same, and orbit the walnut.

Escape velocity is the velocity required to escape the earth's
gravitational field (go up and not come down at all). What we call
"orbital velocity" is the velocity required to remain in a circular
orbit around the earth, at an altitude of about four thousand miles
above the earth's center. At the apogee of a sufficiently elliptical
orbit, the actual velocity can be arbitrarily small.

Jose
--
You can choose whom to befriend, but you cannot choose whom to love.
for Email, make the obvious change in the address.

writes:

Up, then down, until it hits what someone so nicely described as 'the
hard edge of the sky". Is your assertion that is orbital?

Absolutely. The orbit doesn't seem like an orbit because it intersects the
planet's surface, but if the Earth were a dimensionless point with the same
mass, the track would be an ellipsoidal orbit around that point.

Ballistic tracks at the surface are the very tips of very eccentric orbits
that intersect the Earth.

Jose writes:

Suppose that, as the rock was passing through the soft part of the sky
(we neglect air friction because this is powered freefall flight), the
earth shrunk to the size of a walnut. The flight path would stay the
same, and orbit the walnut.

Exactly. At least someone here is capable of abstract thinking.

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.

Mxsmanic wrote in
:

Rip writes:

Anthony, that statement makes a road-kill 'possum smarter than you.
Try again, and get back to us when you've figured out your error.

Get back to me when you're ready to explain the alleged error.




I'll tel you what the error is for $400.

Bertie



























I'll tell you what it is for

The intitial velocity limitation says 'vertical'.

I haven't really been following the thread, so I don't know what the
initial thing is (except, by the thread title, that it's a
miscommunication about whether the 1g force one feels standing still is
to be "counted" or not, and whether a degenerate case of the barrel roll
"counts".

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

True. But if there is =no= horizontal component, you don't have a very
interesting maneuver.

btw, is a satellite "in orbit" if it blows up before it completes a
complete revolution (even though it would have completed it just like
any other orbiting satellite?)

Even if there was, by the way, the Newtonian physics demand the path
will cross the starting point,

True (fsvo starting point)

and the implication to most readers
would be that was on a surface.

Depends on the situation. Rockets start from the surface, but don't
"enter orbit" until they are far from that surface (yes, this involves
acceleration).

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.

If by "impulse" you mean "instantaneous change in velocity" then you
would need the launching surface (if there be one) to move out of the
way. But you don't need a launching surface. You can jump into the air
(vertically) and then apply a (huge) impulse horizontally while you are
still airborne, and you will be in orbit. (IF we are talking about
instantaneous impluses, why not extend the fantasy)

If by impluse you merely mean "very fast change in veolocity", then
there will be some value of "very" for which you can avoid impact.

Jose
--
You can choose whom to befriend, but you cannot choose whom to love.
for Email, make the obvious change in the address.

Mxsmanic wrote in
:

El Maximo writes:

I'm sure there are enough definitions of orbit for you to choose from
that you wouldn't bother learning, only arguing.

In other words, I am not in error.


Yes, you are. You are always in error.


Bertie

Mxsmanic wrote in
:

Jose writes:

Suppose that, as the rock was passing through the soft part of the
sky
(we neglect air friction because this is powered freefall flight),
the
earth shrunk to the size of a walnut. The flight path would stay the
same, and orbit the walnut.

Exactly. At least someone here is capable of abstract thinking.


Nope. Worng again fjukkktard.


And if you find everyone so tedious, why stay?

I know why, don't I fjukktard?


Bertie