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paul Offline OP
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Quote:
Two identical 1kg objects, each travelling at 4000m/s collide head on and stick together. After they stick together you say the 2kg blob will be moving at 4000m/s.


its a good thing we were discussing an elastic collision otherwise you would be correct.

http://en.wikipedia.org/wiki/Elastic_collision

Quote:
An elastic collision is an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter. Elastic collisions occur only if there is no net conversion of kinetic energy into other forms.


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paul Offline OP
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in reference to the link you posted and the first flash
collisions in 1-d

if you replace the mass A with 1000 kg
and
mass B with 100 kg

mass A being the 1000 kg pipe
mass B being the 100 kg mass

and velocity of A to 4 m/s

you will see that mass B ( which would be the mass ) in our discussion almost doubles the velocity of mass A.

it would be nice if you could find a flash as in the above that would actually have a mass passing through a turn.

that you could set the mass and velocity of each.

the flash is not correct because if you set both A and B to 1000 kg and set the velocity of A to 1 m/s
you end up with more kinetic energy than you started with.

A with a velocity of 0.9 m/s
B with a velocity of 1.0 m/s

the kinetic energy you started with was
A and a velocity of 1.0 m/s

so the flash must be wrong.





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I'm not sure what this has to do with weather in NZ; however, when I run the example, it shows conservation of momentum. The display is a little confusing.

For e=1 (perfect elasticity)
Before:
Ma = 3 Kg Va=2ms­ˉ¹
Mb = 1 Kg Vb=0msˉ¹

Total momentum before = 6 Kgms­ˉ¹

After:
Ma = 3 Kg Va=1ms­ˉ¹
Mb = 1 Kg Vb=3msˉ¹

Total momentum after = 6 Kgms­ˉ¹

From the given web page
http://www.splung.com/content/sid/2/page/momentum)

" * An elastic collision is a collision where the both the momentum and the kinetic energy are conserved."

" * In an inelastic collision the momentum is conserved but the kinetic energy is not. In fact the kinetic energy will be lower after the collision because some energy has been used in creating sound, deformation and heat. The reality is that most collisions are inelastic to some extent. However, collisions between snooker balls come quite close to being elastic collisions."

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Originally Posted By: paul
its a good thing we were discussing an elastic collision otherwise you would be correct.

So your law of conservation of momentum only applies when energy is also conserved. My law applies all the time, no matter what.

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Originally Posted By: paul
if you replace the mass A with 1000 kg
and
mass B with 100 kg
and velocity of A to 4 m/s

In this case the animation agrees with both of us because there is no direction change. Try it with a direction change like my example and compare to your momentum law.


Quote:

the flash is not correct because if you set both A and B to 1000 kg and set the velocity of A to 1 m/s
you end up with more kinetic energy than you started with.

I think you mistyped something there. Have another go. Make sure e=1 to conserve kinetic energy.

Last edited by kallog; 09/15/11 12:36 AM.
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paul Offline OP
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someone must have fixed it because it was showing the numbers I posted , maybe it showed up the wrong numbers because I was changing the values around so much before.

but it is showing the right numbers now.


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http://www.convertalot.com/elastic_collision_calculator.html

Use this. It can represent our 1st turn.

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paul Offline OP
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its working right now , anyway I messed around with it a bit and I input 4000 kg as mass B and 100 as mass A
and the elasticity as 1

I used 4000 kg because mass B (the pipe) would have
4000 kg m/s
1000 kg x 4 m/s = 4000 kg m/s

and the result is
-38.049 m/s for va
and
1.951 m/s for vb

I believe that if mass B were traveling towards A at 4 m/s
then mass B would stop and mass A would double velocity to
-80 m/s

the resultant movement of the
4000 kg mass B to 1.951 m/s = 7804 kg m/s
we might as well say there was 8000 N.s in the collision
and 8000 N.s would accelerate the 100 kg mass to -80 m/s

of course with multiple pipe and mass sets you wouldnt even stop the pipe at all.

because there would always be say 20 masses accelerating and 1 mass in 1 of the 1st turns and 1 mass in 1 of the 2nd turns and 20 masses would be free floating to the 2nd turns.

the array would consist of 42 sets of pipes and masses.
each pipe with a mass of 1000 kg
each mass with a mass of 100 kg

so you would actually have

100 kg x 40 m/s = 4000 kg m/s , each mass
4000 kg m/s x 20 = 80,000 kg m/s , array of 20 sets accelerating
or 80,000 N.s

vs

nothing because there is 1 mass in the 1st and 2nd turns.
and they cancel each other out.





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paul Offline OP
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http://www.convertalot.com/elastic_collision_calculator.html

that is an object colliding with another object traveling in the same direction.

it wouldnt work.



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Quote:

it wouldnt work.


No, here I'll try it -

m1 = 1000kg
m2 = 100kg
vi1 = 4m/s
vi2 = -40m/s

... calculator ...

vf1 = -4 m/s
vf2 = 40 m/s

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mass A = 100kg
mass B = 1000kg
initial speed of mass A = 40m/s
Originally Posted By: paul
I believe that if mass B were traveling towards A at 4 m/s
then mass B would stop and mass A would double velocity to
-80 m/s

That would violate both conservation of momentum and conservation of energy.

Paul, you say you know what magnitude means and you say you know what momentum means, but you don't. Please please look up "momentum" on google instead of repeating the same mistakes over and over again.

Last edited by kallog; 09/15/11 03:22 PM.
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https://www.msu.edu/~brechtjo/physics/airTrack/airTrack.html

Red cart: 1000, 4
Blue cart: 100, -40


After collision:

Red cart: -4
Blue cart: 40

Different app, exactly the same result, exactly as I predicted.

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paul Offline OP
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Quote:
That would violate both conservation of momentum and conservation of energy.


I did reply to this then I found your post with the applet link.

so I changed this reply.
that applet makes things much better.

according to the applet you are right.



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paul Offline OP
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kallog
https://www.msu.edu/~brechtjo/physics/airTrack/airTrack.html
the above applet you posted a link to proves that reactionless propulsion is possible and that is basicaly what this has all been about anyway.

set the red cart mass to 5 kg , initial velocity to 40 m/s
set the blue cart mass to 1000 kg , initial velocity to -4 m/s

set elasticity to m1 = m2 elastic
the results are as follows.

the red cart -47.56 m/s
the blue cart -3.56 m/s

the red cart ( 5 kg mass ) accelerates from 40 m/s to -47.56 m/s

the blue cart (pipe / rails) do not stop they only slow down.
to -3.56 m/s from -4 m/s

if you are using multiple rail and mass sets.

I increased the lenght of the pipe / rails to 1000 m
but to make this easier lets say the new pipe / rails length is only 400 meters.

400 / 20 = 20

say 20 masses are accelerating at any given time.
so you would have 20 masses free floating and 1 mass in the turns at each end.

a total of 42 masses.

the 20 rails have a combined mass of 1000 kg
each mass that is accelerated has a mass of 5 kg

20 x 5kg = 100 kg

each mass starts at the begining of the 400 meter rail
and they are timed to begin acceleration so that there will be 20 masses accelerating at any given time.

1 is launched then a time passes then another and so on.
this way the distance of the 5 kg masses will be spaced in their respective rail gun so that only one 5 kg mass enters the 1st turns at a time.

each mass is accelerated to 40 m/s
this in turn accelerates the 20 rails to -4 m/s
because there are always 20 masses being accelerated at any given time.

20 x 5 kg = 100 kg

so each time a single 5 kg mass collides with the pipe / rails that is traveling at -4 m/s the mass ( red cart )
reverses direction and has a velocity of -47.56 m/s

the pipe / rails does not even stop or reverse direction it only slows its velocity from -4 m/s to -3.56 m/s

so theres proof that it will work.

but lets not forget that there will also be a mass passing through the 2nd turns as well so

so change the mass of the red cart to 1000 kg
change the mass of the blue cart to 5 kg
copy the resultant -3.5621890547263684 velocity from the blue cart to the red carts initial velocity

copy the resultant velocity -47.56218905472633 from the red cart to the blue carts initial velocity

run it and you see that as the two masses pass through the 1st and 2nd turn they cancel each other out.
like I have always said.
chances are that once the system is in opperation the pipe never would even slow down...

results are as follows

red cart -4 m/s
blue cart 40 m/s (39.999999999999964) actual


now to make it so that there is no movement before your ready to go , you could have accelerator rails where the masses free float , and synchronized launching of the masses from the + direction rails and from the - direction rails would cause the pipe / rails to not move.



if you want to go forwards or backwards you just shut down the accelerator that you dont need to travel in that direction.


and it wouldnt cost more than 18 billion to build and it would be as if our technology isnt still stagnated.

using the same exact space propulsion as we have for the last 60 or 70 years or so.





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Now we agree what happens a little more:

Before starting:
pPipe = 0
pMass = 0
pTotal = 0

After the acceleration:
pPipe = 4000Ns
pMass = -4000Ns
pTotal = 0

After the 1st turn:
pPipe = -4000Ns
pMass - 4000Ns
pTotal = 0

After the 2nd turn:
...

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Originally Posted By: paul
say 20 masses are accelerating at any given time.

Isn't this supposed to work with just one mass? Stick to 1 mass until you clearly acknowledge that it cannot work at all with just one mass.

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I have the urge to program one of those animations myself, but with the full blown pipe and accelerator. I know it won't convince you but I think I just want to do it for fun!

OK, did it:

http://dl.dropbox.com/u/21857463/tube.exe


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paul Offline OP
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just paste the code on the forum.
Im not in the habit of opening .exe's off the web.


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paul Offline OP
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Quote:
After the 1st turn:
pPipe = 4000Ns
pMass = -4000Ns
pTotal = 0


did you follow what I did on the applet you posted?
https://www.msu.edu/~brechtjo/physics/airTrack/airTrack.html

set the red cart mass to 5 kg , initial velocity to 40 m/s
set the blue cart mass to 1000 kg , initial velocity to -4 m/s

set elasticity to m1 = m2 elastic
the results are as follows.

the red cart -47.56 m/s
the blue cart -3.56 m/s

the red cart ( 5 kg mass ) accelerates from 40 m/s to -47.56 m/s

the blue cart (pipe / rails) do not stop they only slow down.
to -3.56 m/s from -4 m/s

you must be capable of thinking about using the
42 rail and mass sets and the 20 masses accelerating as described above.

for us to continue.

Quote:
Isn't this supposed to work with just one mass? Stick to 1 mass until you clearly acknowledge that it cannot work at all with just one mass.


heres an example.

you have a water pail that has a small hole in it at its bottom.

you want to carry 1 oz of water for a distance of 399 meters.
the pail can initially hold 400 oz of water.

but the small hole leaks 1 oz per second.

you have the ability to run 1 meter per second so you can make it the distance of 399 meters and still have 1 oz of water remaining in the water pail.

but if you only put 1 oz of water in the pail you will never achieve your goal.





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Originally Posted By: paul
but if you only put 1 oz of water in the pail you will never achieve your goal.


You mean to say IT CANNOT WORK WITH ONE MASS!!!?

So now we agree that IT CANNOT WORK WITH ONE MASS!!

Does that mean you can agree with my calculations for one mass? You retract your claims that it would work with one mass?

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