New member writes...

Thankyou all for your contributions,

Unfortunately I could not read Al Globus' posting due to a 'broken
pipe'(???)

I'm pretty sure that at 100m from axis, an accelartion of 9.8ms^-2 is
achieved at a rotation speed of about 31ms^-2 (SQRT(9.8*100)) but it's
not about getting bogged down with numbers.

Lucio's explanation makes absolute sense. My way of thinking came
from reading somewhere that it was easier to walk in one direction
rather than the other, can anyone explain what the physical
explanation for this is and the numerical magnitude of the
opposition/assistance to movement?

Best wishes,

John

--- In spacesettlers@y..., Lucio de Souza Coelho wrote:
> From:
> To:
> Sent: Tuesday, October 30, 2001 7:40 AM
> Subject: [spacesettlers] New member writes...
>
> [snikt]
> > If my Maths is correct, a colonies 'floor' rotating about 100
metres
> > from its axis would have a rotation speed of about 30 metres per
> > second, this is remarkably fast. If one was to walk against the
> > direction of orbital motion, surely their strides would be
> > unmanageably large due to the combined effect on the rotating
floor
> > and their own movement.
> > The only thing I can think of is friction by the ground on the
other
> > foot. Also, what if they jumped in the air?
> >
> > How will people in these colonies get from A to B?
> >
> You're doing a common mistake by using "intuitive physics". You're
assuming
> that, somehow, a person gets completely still as soon as it looses
contact
> with the inner surface of the colony (e.g., by jumping). But in fact
people
> have inertia, and a person that jumps inside your colony with a 100
meters
> radius will *also* have a speed of 30 m/s perpendicular to the
rotation
> axis - exactly the same tangent velocity of the floor. Since the
floor and
> the person have speeds of the same value and direction, the floor
will in
> fact look still for the person jumping - as when he or she jumps on
Earth.
>
> "Intuitive physics" also tell things like "a bomb dropped from a
plane will
> follow a straight line to the surface and hit the point that was
below the
> plane at the moment when the bomb was dropped". But in fact bombs
dropped
> from planes follow a *parabolic* trajectory, due to the same
inertial