[geocentrism] more slingshot.
- From: "Philip" <joyphil@xxxxxxxxxxx>
- To: <geocentrism@xxxxxxxxxxxxx>
- Date: Sat, 12 Feb 2005 16:40:52 +1000
Escape velocity...
Well this I think conforms with what I said last post. It makes sense and
agreees with my thoughts . And Mike you did not tell me true. Close but not
true. I was right , what goes up must come down... Neville may have won.. given
infinity. of time, even though Neville I think you do not accept that the force
of gravity extends to infinity.
Remember the story of the tortoise every hour he gets to travel half the
distance remaining. When will he arrive?
"Defined a bit more formally, "escape velocity" is the initial speed required
to go from an initial point in a gravitational potential field to infinity with
a residual velocity of zero, relative to the field. Conversely, an object
starting at rest and at infinity, dropping towards the attracting mass, would
reach its surface moving at the escape velocity.
He he! I like it... Se the more general explanation.below...BUT PLEASE LOOK
CLOSELY AT THE LAST PARAGRAPH. If the figures are correct, and I have no reason
to doubt they are, then indeed we have to look very hard to find another reason
rather than that the world rotates on its axis. Can we then please get on to
the main task of our cause.... the immobile earth. We are a long way from
proving that one with any provable demonstration of natural science.
Philip.
From Wikipedia, the free encyclopedia.
For the video game title, see Escape Velocity (computer game).
In physics, for a given gravitational field and a given position, the escape
velocity is the minimum speed an object without propulsion, at that position,
needs to have to move away indefinitely from the source of the field, as
opposed to falling back or staying in an orbit within a bounded distance from
the source. The object is assumed to be influenced by no forces except the
gravitational field; in particular there is no propulsion, as by a rocket,
there is no friction, as between the object and the Earth's atmosphere (these
conditions correspond to freefall) and there is no gravitational radiation.
This definition may need modification for the practical problem of two or more
sources in some cases. In any case, the object is assumed to be a point with a
mass that is negligible compared with that of the source of the field, usually
an excellent approximation. It is commonly described as the speed needed to
"break free" from a gravitational field.
One somewhat counterintuitive feature of escape velocity is that it is
independent of direction, so that "velocity" is a misnomer; it is a scalar
quantity and would more accurately be called "escape speed". The simplest way
of deriving the formula for escape velocity is to use conservation of energy,
thus: in order to escape, an object must have at least as much kinetic energy
as the increase of potential energy required to move to infinite height.
Defined a bit more formally, "escape velocity" is the initial speed required to
go from an initial point in a gravitational potential field to infinity with a
residual velocity of zero, relative to the field. Conversely, an object
starting at rest and at infinity, dropping towards the attracting mass, would
reach its surface moving at the escape velocity. In common usage, the initial
point is on the surface of a planet or moon. On the surface of the Earth the
escape velocity is about 11.2 kilometres per second. However, at 9000 km
altitude in "space", it is slightly less than 7.1 km/s.
For a body rotating about its axis the escape velocity with respect to the
surface does depend on direction. E.g., for the Earth the rotational velocity
is 465 m/s to the east at the equator, and the escape velocity to the east,
with respect to the Earth's surface, is ca. 10.7 km/s.
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- » [geocentrism] more slingshot.
