In the article about aeroplanes , we saw that it is the wings that
give it flight and not the engine. So how do rockets manage to fly yet
they don't have wings?Well, actually, some rockets do have wings. If
you closely look at the ones used in ballistic missiles, you will
notice small wings usually near the front end. But the ones for
delivering satellites into outer space are normally wingless.These
satellite delivery rockets do not stay in the sky; they are usually
dropped off once their job is done and they fall back to the ground
(okay, usually in the oceans) and the satellite is then left in orbit
where it stays without needing any additional propulsion. This is
probably the more intriguing kind of flight. In the aeroplane article,
we saw how the flow of air over the wings provides the upward lifting
force. But there is no air in outer space, so how do the satellites
manage to stay up there?Many people think that there is no gravity in
space, but that is a misconception — there is gravity and if we
weren't careful, the satellites would indeed fall back to earth. To
better understand how they stay up there, let's do a simple
thought-experiment. If you pick a stone and throw it away, it is
common knowledge that the harder you throw it, the farther it will
fall.Now, bearing in mind that the earth is spherical in shape, we can
then appreciate that the farther away you throw the stone, the closer
it gets to you from behind. A question that arises: Is it possible to
throw an object so hard that it travels all the way round and comes
back to the starting point?The answer is, surprise, surprise, yes! And
this is the trick used in a satellite. It is accelerated to such a
high velocity so that it flies all the way past the starting point.
That way, it stays in an orbit around the earth without the need for
wings.Still, doesn't the satellite need to be propelled continuously
once it has reached its orbit?The answer to this question comes in the
form of a question: What would slow down the satellite? When things
are moving on the ground they are slowed by friction; objects flying
in the air are slowed down by friction between their surface and the
air.In outer space, there is no friction, therefore, there is no need
for additional propulsion once the desired orbit has been
reached.However, life isn't perfect and there are small amounts of air
at the typical altitude of satellites. For this reason, satellites
need an occasional slight push to take them back to the designated
height.And the engines required for this are not very powerful — some
of them can't even lift a baby off the ground.
--
When I quote others I do so in order to express my own ideas more clearly.
http://gainmoneyfast.com/-67102.htm
give it flight and not the engine. So how do rockets manage to fly yet
they don't have wings?Well, actually, some rockets do have wings. If
you closely look at the ones used in ballistic missiles, you will
notice small wings usually near the front end. But the ones for
delivering satellites into outer space are normally wingless.These
satellite delivery rockets do not stay in the sky; they are usually
dropped off once their job is done and they fall back to the ground
(okay, usually in the oceans) and the satellite is then left in orbit
where it stays without needing any additional propulsion. This is
probably the more intriguing kind of flight. In the aeroplane article,
we saw how the flow of air over the wings provides the upward lifting
force. But there is no air in outer space, so how do the satellites
manage to stay up there?Many people think that there is no gravity in
space, but that is a misconception — there is gravity and if we
weren't careful, the satellites would indeed fall back to earth. To
better understand how they stay up there, let's do a simple
thought-experiment. If you pick a stone and throw it away, it is
common knowledge that the harder you throw it, the farther it will
fall.Now, bearing in mind that the earth is spherical in shape, we can
then appreciate that the farther away you throw the stone, the closer
it gets to you from behind. A question that arises: Is it possible to
throw an object so hard that it travels all the way round and comes
back to the starting point?The answer is, surprise, surprise, yes! And
this is the trick used in a satellite. It is accelerated to such a
high velocity so that it flies all the way past the starting point.
That way, it stays in an orbit around the earth without the need for
wings.Still, doesn't the satellite need to be propelled continuously
once it has reached its orbit?The answer to this question comes in the
form of a question: What would slow down the satellite? When things
are moving on the ground they are slowed by friction; objects flying
in the air are slowed down by friction between their surface and the
air.In outer space, there is no friction, therefore, there is no need
for additional propulsion once the desired orbit has been
reached.However, life isn't perfect and there are small amounts of air
at the typical altitude of satellites. For this reason, satellites
need an occasional slight push to take them back to the designated
height.And the engines required for this are not very powerful — some
of them can't even lift a baby off the ground.
--
When I quote others I do so in order to express my own ideas more clearly.
http://gainmoneyfast.com/-67102.htm
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