[geocentrism] Re: acceleration calcs
- From: Paul Deema <paul_deema@xxxxxxxxxxx>
- To: Geocentrism@xxxxxxxxxxxxx
- Date: Tue, 18 Mar 2008 15:25:47 +0000 (GMT)
Allen D
It may be that I just don't understand your descriptions -- heaven knows I am
not alone and you do little to ameliorate this -- but I'm going to proceed on
the basis that I do understand what you are saying. I'm not going to address
your objections point by point -- that is a quagmire that I for one have been
bogged down in more than once. I'm going to be charitable and assume that you
still do not grasp what I'm saying about accelerometers.
An accelerometer is a mass suspended in some manner, such as by a spring, in a
vehicle which is to be accelerated. Now if we were to hang this device from a
stationary beam in a 1 'g' gravity field, and it has a mass of 1 kg, then the
spring will be extended, coming to a halt when the spring exerts an upward
force of 1 kg. If the accelerometer is properly calibrated, it will read 1 kg.
If you repeat the experiment on the Moon, it will read -- roughly -- 0.166 kg.
If we take the accelerometer and mount it in a space vehicle in free fall, it
will read 0 kg. If we initiate a rocket burn, and the accelerometer reads --
while the motor is firing -- 1 kg, then we can state that our acceleration is
equal to what we would feel standing on the Earth -- an acceleration of one
'g'. Thus the extension of the spring is an exact analogue for the amount of
acceleration being experienced. It relies for its operation on Newton's first
law of motion and Hooke's law of
elasticity.
There is another way we could utilise the accelerometer to determine our
acceleration in a space vehicle. Let us assume again that we are in space in
free fall and we are about to initiate a rocket burn. This time, instead of
gluing our eyes to the accelerometer, we detach the 1 kg mass and place it
outside the vehicle in free fall with velocities matched. We initiate our
rocket burn, and with some radar or laser device we continuously measure the
distance to the 1 kg mass. If we integrate the readings over time, we can
calculate our acceleration.
Now for the crunch, the bit where our velocity changes due to acceleration by
gravity. (Note - from a recent post from Regner, perhaps 'speed' is more
appropriate here -- please comment if you think it appropriate. In any event,
what I'm trying to convey is that our rate of travel increases). This time, we
place our vehicle into elliptical orbit -- around Earth will suffice -- and as
we pass apogee, we begin to accelerate. At this moment we place our
accelerometer 1 kg mass outside the vehicle with velocities matched and engage
our distance and time measuring devices. After we have passed perigee we will
have stopped accelerating and begin decelerating. At no time from apogee to
perigee will the 1 kg mass have fallen behind or overtaken us and this will not
change from perigee back to apogee and so on for ever and ever amen. Despite
acceleration and deceleration due to gravity in an elliptical orbit, our
accelerometer will indicate no change in velocity.
Paul D
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www.yahoo7.com.au/y7mail
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