Let's say an astronaut is tied to a rope. Attached to a

He will push himself away from the rock and travel at minimal speed as the rope goes taught.

>>8129583
he will hit the rope with the same force as he applied to the rock and it will stop the rope

There's no external forces therefore the man/rock system won't move.
Op plus go download us physics book with newton's laws

>>8129583
Is he moving his center of mass? No? Well then you have your answer.

>>8129619
wrong, the external force is the weight of the rock and its velocity

newtons third law. take your own advice

think of what would happen with something light like frog and a big rock on earth. it would fly the fuck away. If you had something like the Canadarm throw you then yes you would fly in a certain direction

>>8129628
plz be bait?

its a closed system, because they are tied together. any change of inertia the man imparts on the rock, he must impart on himself as well such that the total momentum is zero.

you didnt just invent a massless propulsion system based on rocks and ropes after all, you fucking idiot. you dont think NASA or the Russians would have thought of that already if it wasnt braindead stupidly impossibly wrong?

>>8129647
ok but imagine if a third source threw him and the rock

>Let's say OP is tied to a rope. Attached to the rope is a giant rock. If we toss the rock off a bridge into the ocean, will anything of value be lost?

>>8129647
That actually made me laugh way too hard.


Anon is right. If the astronaut pushes on the rock with force x he will experience force x backwards and will accelerate backwards with x/(his mass). When the tension in the rope catches then he will experience force x forward and end up at 0 velocity.

If the rope breaks or there is no rope then you've essentially created a ghetto rocket (of sorts) ie: throwing mass one waybto propel an object another way.

Tldr it's a closed system so there is no net force.

>>8129659
why?

Then the man and rock would go flying thru space with equal and opposite momentum as the third source would impart on itself.

And then the third source wouldnt be able to throw them again, or do you want to attach YET another rope and now we are back to square one. Unless you have a fourth source and another rope and a fifth and a rope and a....

its turtles all the way down

Then why is it that if an astronaut takes off his jetpack and kicks off if it he will travel in the opposite direction?

>>8129623
Classical Newtonist.
kek

>>8129676
Because he isnt tied to it you jackass. But even in that case, the center of mass of the system containing the astronaut and his jetpack will NOT change.

>>8129676
>Then why is it that if an astronaut takes off his jetpack and kicks off if it he will travel in the opposite direction?
Because it is no longer a closed system, the jetpack is not physically connected to the astronaut and thus has it's own inertia. When the astronaut kicks the pack away, the same force exerted on the pack is exerted on him, and so he goes off in the opposite direction.

>>8129623
>his center of mass

I think you mean the center of mass of the system.

>>8129686
What is the astronaut has a heavier rock tied to a 50 ft rope, and a lighter rock tied to a 35 ft rope, and throws the lighter rock in his intended direction of travel?

>>8129704
Or pushes off the heavy rock then throws the lighter rock?

>>8129704
How does that change anything?

File: None of this matters.jpg (872KB, 1600x1036px) Image search: [Google]

872KB, 1600x1036px

>>8129755
It doesn't, everyone is just shitposting now!

>>8129583
no

however if he tore off chunks of his flesh and ejected them at a high velocity he could slowly build up speed and go anywhere, until he ran out of body parts

A clever astronaut would position himself in stable, perfectly circular, equidistant and equatorial orbit around Earth and throw the stone such that he'll meet it again on the other side. There, he'll grab it and quickly throw it again the same way when he flies by, and so on.
Climb the stars, baby.

>>8129849
Oh, the astronaut will have to account for orbital motion of Earth as well. He'd need to adjust the force of his throw such that he'll meet it in exactly n years, where n is any integer. Also, the stone will need to have the same mass as him. Also, there can't be any other gravitational wells to disturb him or the stone anywhere close.

>>8129647
>you didnt just invent a massless propulsion system

what if there are 2 (two) astronauts throwing a football back and forth?

checkmate, scientists

>>8129849
>A clever astronaut would position himself in stable, perfectly circular, equidistant and equatorial orbit around Earth and throw the stone such that he'll meet it again on the other side.
I don't think there actually any interesting solutions to that. If the rock meets up with the astronaut again, then neither of them will have gone anywhere.

>>8129869
>what if there are 2 (two) astronauts throwing a football back and forth?
A propulsion system that uses another person as mass.