"John Williamson" wrote in message
...
dennis@home wrote:


"John Williamson" wrote in message
...
The Natural Philosopher wrote:
John Williamson wrote:
dennis@home wrote:


"The Natural Philosopher" wrote in message
100mph is too fast to go through a town center but isnt fast enough
to escape to earth orbit.

That's not true.
its more than enough to escape earth orbit.
Go on argue with me and prove that you have no understanding of
orbits or space travel.

Escape velocity from the Earth is 25,000mph, roughly. Orbital speed
for the Earth at ground level is about 17,500 mph relative to the
centre. At 100mph on a normal road, the reduction in weight is in
theory just about measurable, although in practice totally masked by
aerodynamic effects.

100mph is a *touch* too fast to be driving through a town centre,
though, unless you're in Monaco on Grand Prix day.


Note dennis changes the game from 'to earth orbit' to '[from?] earth
orbit'.

And is still wrong.

Where?
Are you denying physics by saying a rocket with an engine that can run
long enough can't escape the earths gravity at very slow speeds?

No, I'm calling your statement which say that 100mph is fast enough to
escape Earth orbit a lie. Unless, of course, you are talking about an
extra 100 mph for an object that is already travelling at 24914 mph
relaitve to the centre of the Erath.

So you want to start including the speed we are doing because the earth
rotates (about 1000 mph) so you can fine everyone for speeding?

Suppose you are floating stationary in space (relative to the earth as you
would be doing a few thousand mph following the earths orbit around the
sun).
You start to fall towards earth because of gravity (lets call it dead drop).
You now apply thrust away from earth and you start to move at 1 mph, you
then reduce the thrust so you always travel away from the earth at 1 mph.
After a period of time you will have gone far enough away that you are no
longer going to fall back to earth because of gravity.
I.E. you didn't need anywhere near escape velocity to actually get away.

As I said escape velocity is just the speed at which you have enough kinetic
energy stored to escape, if you are generating energy you don't need to go
at escape velocity.
You will never be any good at physics if you can't grasp something that
simple.

But just to make it easy for you, imagine its a car going uphill, you can
either start really fast and get to the top by momentum *or* you can start
the engine and go up at 5 mph (arbitrary speed chosen so you don't have to
think).