# Spanner Propulsion

TheGambit
Posers and Puzzles 22 Aug '05 14:12
1. 22 Aug '05 14:12
If one was in outer space, and for argument's sake not near any gravitational pulls, and you threw a spanner........would you be propelled backwards at the same time as the spanner going forward?
2. PBE6
Bananarama
22 Aug '05 17:13
Originally posted by TheGambit
If one was in outer space, and for argument's sake not near any gravitational pulls, and you threw a spanner........would you be propelled backwards at the same time as the spanner going forward?
Yes. This seems to be a simple application of Newton's 3rd Law, colloquially stated as "for every action there is an equal and opposite reaction."

As you apply a force to the spanner, the spanner applies an equal and opposite force on you, thrusting you backwards. Depending on how you throw it (thrown like a baseball or simply pushed forwarded in a straight line) there could be some spinning involved, but basically you would move in an opposite direction to the spanner.

As for the speed measured from your original position, you would move quite a bit slower than the spanner because you have more mass (unless you're Kate Moss).
3. ark13
Enola Straight
22 Aug '05 18:12
I was an astronaut.
4. PBE6
Bananarama
22 Aug '05 18:36
Originally posted by ark13
I was an astronaut.
Two things to say here:

(1) In space, pee-pee doesn't run down because there's no gravity, but rather around because of surface tension forces. If left unchecked, the last few drops would try to encapsulate your body. To combat this, the astronauts have special urinals which are basically vacuums connected to a "different kind of hose".

(2) If that is the case, why would anyone ever leave the shuttle?? π
5. sonhouse
Fast and Curious
22 Aug '05 21:16
Originally posted by PBE6
Two things to say here:

(1) In space, pee-pee doesn't run down because there's no gravity, but rather around because of surface tension forces. If left unchecked, the last few drops would try to encapsulate your body. To combat this, the astronauts have special urinals which are basically vacuums connected to a "different kind of hose".

(2) If that is the case, why would anyone ever leave the shuttle?? π
And this has to do with spanner propulsion how?
BTW what do you do when you run out of spanners?π
6. Bowmann
Non-Subscriber
22 Aug '05 23:39
Originally posted by sonhouse
BTW what do you do when you run out of spanners?π
Use flies?
7. 08 Sep '05 11:13
ehm, so that's what goes for men, what happens when ladiesare involved???
8. 08 Sep '05 16:01
Which is why unfortuneately , ladies have never gone to outer space as far as I know .
9. sonhouse
Fast and Curious
13 Oct '05 05:501 edit
Originally posted by PBE6
Two things to say here:

(1) In space, pee-pee doesn't run down because there's no gravity, but rather around because of surface tension forces. If left unchecked, the last few drops would try to encapsulate your body. To combat this, the astronauts have special urinals which are basically vacuums connected to a "different kind of hose".

(2) If that is the case, why would anyone ever leave the shuttle?? π
of course it is theoretically possible to have a piss rocket, the plumbing
is even arranged so you can aim it in differant directions,
at least for guys. You could have a flextube for the girls, should
work the sameπ
10. Alcra
Lazy Sod
13 Oct '05 06:071 edit
Originally posted by SicilianNajdorf
Which is why unfortuneately , ladies have never gone to outer space as far as I know .
They have, and they use some elaborate "vacuum" device.

Edit: Men also have a hole for defacation, #2 anyone?
11. 13 Oct '05 14:49
Moving on from Spanners in space, and back to earth..........

If there is no wind present, the temperature is 75 degrees farenheit and humidity is at 35%, would one do a backflip if one sneezed and farted at the same time?
12. UmbrageOfSnow
All Bark, No Bite
13 Oct '05 14:59
Originally posted by TheGambit
If one was in outer space, and for argument's sake not near any gravitational pulls, and you threw a spanner........would you be propelled backwards at the same time as the spanner going forward?
Keep in mind that you can never escape anything's gravitational pull. Gravity is only weaked by distance, it doesn't disappear. So you would have to be in a place where gravity was equal in all directions, cancelling itself out, but you can't be away from any gravitational pulls. Also, if it was completely neutral like that, eventually, you and the spanner would be pulled back together by your own gravity.
13. 13 Oct '05 16:55
Originally posted by UmbrageOfSnow
Also, if it was completely neutral like that, eventually, you and the spanner would be pulled back together by your own gravity.

Actually I think it there is a speed you can throw it (escape velocity) so it will never return. I was just playing with the numbers and am finding some wierd stuff. Physics people double check me on this...

Force o ...[text shortened]... the spanner out of the cannon at some crazy speed, say 30000 m/s, it would still come back to you???
14. XanthosNZ
Cancerous Bus Crash
13 Oct '05 16:57
Originally posted by UmbrageOfSnow
Keep in mind that you can never escape anything's gravitational pull. Gravity is only weaked by distance, it doesn't disappear. So you would have to be in a place where gravity was equal in all directions, cancelling itself out, but you can't be away from any gravitational pulls. Also, if it was completely neutral like that, eventually, you and the spanner would be pulled back together by your own gravity.
Escape velocity.

Also points of zero gravity are points not areas. The L point for example, the point between the Earth and the Moon where the forces from each cancel.
15. 13 Oct '05 16:58
Originally posted by UmbrageOfSnow
Also, if it was completely neutral like that, eventually, you and the spanner would be pulled back together by your own gravity.
Sorry! It might help if I didn't put my message in the 'previous post' box. Heres what its supposed to be:

Actually I think it there is a speed you can throw it (escape velocity) so it will never return. I was just playing with the numbers and am finding some wierd stuff. Physics people double check me on this...

Force of gravity = F(d) = G*m1*m2 / d^2
(G = gravitational constant, m1 = mass of spanner, m2 = your mass, d = distance between you)

Work required to achieve escape velocity = integral from c to infinity of F(s) ds (c is a constant: the distance between the spanners initial position and your center of gravity)

Compute this integral and you get Work = G*m1*m2/c

Set Work = Kinetic energy = 1/2*m1*v^2 (v = spanner's initial velocity)

Solve for v = sqrt(2*G*m2/c)

So this means if you have a cannon positioned exactly at your center of gravity (so c = 0), and launch the spanner out of the cannon at some crazy speed, say 30000 m/s, it would still come back to you???