Collisions

[Zelos]

it aint possible to messure it EXACLY on earth. but it is in space and I think they have done it. and I know im right shvarz, wasent it you who know much about science? and the law of conservation tells that momentum cant disaphere or come from nowhere. man ur so 3 dimensianal shvarz

[PurpleYouko]

Nobody ever said you could make momentum from nothing or disipate it to nothing.

Al we have been saying is that it is impossible to know if the entire momentum in a given system is zero. All we know is that the momentum in the system remains unchanged

If your entire system is on board a speeding spacecraft then its net momentum is shitloads but if it is stationary (with respect to what though?) then it could be zero.

There is just absolutely no way to know what the total momentum for any system is since it is also impossible to know the absolute velocity of any object anywhere. As you are so fond of saying, it's all relative.

[Zelos]

thats what ive been saying, but I have gone from the thought that its most likly to start whit 0 momentum if we start whit a big bang

[Botsareus]

zelos are you saying this:

   A is still
  B is moving toward A
  B(300jingleballs\spuclick) is the speed of B

A<---------------B(300jingleballs\spuclick)

results in

A(0jingleballs\spuclick)B(0jingleballs\spuclick)

?

[Zelos]

ok, bot, use SI units for everything and not the freaking mph, I dont use km/h, do I?
no what im saying is that
AB
a throw away object be and A/B is equal heavy. And B gets V 5m/s then A will get 5m/s in the other direction

[Botsareus]

Not if more effects of friction on A then B....


All good zelos , now it makes more sense....


***
Btw I am more used to km\h myself... who cares.   ok ok , ill change it to jingleballs\spuclick

[Botsareus]

:laugh:

[Zelos]

if you ask me, the last thing was just stupid, when we talk about this we use SI units, which means m/s, but for me mph tell me nothing more than the speed is between 0m/s to C m/s

[Botsareus]

:D So you did get it , good job...

[Zelos]

of course I get it, do you think im somekinda idiot? im insulted. I´ll send you to the coal mines when im done :evil:

[Botsareus]

(just dont start taking yourself seriosly)

[Numsgil]

Uh, Zelos, I don't understand what it is you're arguing anymore.  Is it that momentum is always conserved in non-curved space time?  Then I think I agree with you, although I don't agree that that actually tells us anything useful, since as PY says, friction and other things have to be measured on the macroscopic level.  Momentum is really only useful directly before and after a collision.

If you're arguing something else, shame on you!

[Zelos]

im not argueing anymore