Can we stop the earth's rotation?

[hotquik]

" Newton's Third law: All forces in the universe occur in equal but oppositely directed pairs. There are no isolated forces; for every external force that acts on an object there is a force of equal magnitude but opposite direction which acts back on the object which exerted that external force."

So... if every person in the world walks ( or runs ) in the direction of the rotation of the earth ( so our feets push the earth in the opposite direction ), could we stop the rotation of the earth ?

 

[mightyrocket]

nolain:

 

[hotquik]

:getlost: why not?

 

[mightyrocket]

because it's the moon which keeps the earth going around. You need to destroy the moon to stop the earth.

 

[hotquik]

:getlost: the moon? doesnt make sense for me...

 

[Tagrineth]

" Newton's Third law: All forces in the universe occur in equal but oppositely directed pairs. There are no isolated forces; for every external force that acts on an object there is a force of equal magnitude but opposite direction which acts back on the object which exerted that external force."

So... if every person in the world walks ( or runs ) in the direction of the rotation of the earth ( so our feets push the earth in the opposite direction ), could we stop the rotation of the earth ?

The net forces would still equal zero - the Earth's rotation would be pushing every person forward faster at the same time.

So no.

 

[Gent]

:getlost: the moon? doesnt make sense for me...

And every person in the world walks ( or runs ) in the direction of the rotation of the earth so thier feet push the earth in the opposite direction , could we stop the rotation of the earth does ? lain:

 

[hotquik]

Re: Re: Can we stop the earth's rotation?

The net forces would still equal zero - the Earth's rotation would be pushing every person forward faster at the same time.

So no.

Yes, we would be walking faster but earth should rotate slower...

 

[hotquik]

Re: Re: Can we stop the earth's rotation?

And every person in the world walks ( or runs ) in the direction of the rotation of the earth so thier feet push the earth in the opposite direction , could we stop the rotation of the earth does ? lain:

what you mean?

 

[icepir8]

there are a few problems here.

the earth to people mass ratio is so much greater than the speed we could walk. The resulting reduction in rotation speed would be so small that i would be near inposible to measure. That doesn't take in considuration of friction and how would you orginize such a large effort.

 

[hotquik]

there are a few problems here.

the earth to people mass ratio is so much greater than the speed we could walk. The resulting reduction in rotation speed would be so small that i would be near inposible to measure. That doesn't take in considuration of friction and how would you orginize such a large effort.

The earth wouldnt stop at once, it would take years maybe....
Remeber is an hipotethic question , so suppose you have all the ppl in the earth at your command
Suppose that you are Brain, and you and Pinky finally conquered the earth

 

[Imoto]

The earth wouldnt stop at once, it would take years maybe....
Remeber is an hipotethic question , so suppose you have all the ppl in the earth at your command
Suppose that you are Brain, and you and Pinky finally conquered the earth

Don't forget: The Atmospehre is turning with the earth, so it doesn't matter in wich direction all humans run or walk.

You may say: very much many fly are walking around a big ball, a really big ball, will the ball start or stopp spinning?

A Fly is about 5mm in high, and 10mm in lengh, the ball has a diameter of more than 5m.

 

[hotquik]

Don't forget: The Atmospehre is turning with the earth, so it doesn't matter in wich direction all humans run or walk.

1) air friction is lot smaller than floor friction, almost zero...
2) if all moving things (most specific than just humans ) would move in the opposite direction of the rotation of the earth, the earth wouldnt eventually rotate faster ?

You may say: very much many fly are walking around a big ball, a really big ball, will the ball start or stopp spinning?

A Fly is about 5mm in high, and 10mm in lengh, the ball has a diameter of more than 5m.

F = m*a

people's force ->
F ppl = m ppl *a ppl

newton's law says->
F ppl = - F friction

earth's friction ->
F friction = m earth * a earth

so
m ppl * a ppl = m earth * (- a earth)

cauz earth's mass is a lot bigger than people's mass, than earth's acceleration should be a lot smaller tha n people's acceleration, but not zero.

Note: i am in a very very boring class right now....

 

[Imoto]

This must be a very boring class, when you write susch things as physic formulas on free will.

 

[hotquik]

Cant describe you how boring it is...

 

[Remote]

It seems like someone has seen The Core...

 

[Jimbot]

look you guys if we all run, or drove our cars, or went really fast in the same direction, then we could stop it, but then as soon as we stop pushing the earth backwards and stop, therefore, pushing it forwards again, it would regain speed. I think...

Actually, i think thats wrong...

Also, its impossible, because the relative masses of all those people is practically nothing compared to the mass of the earth. We could slow it down, but just slightly so that we might be a minute faster (or slower) every year or something.

so no we cant

 

[Remote]

One q: Why would you wan't to stop the earth from rotating?

 

[hotquik]

look you guys if we all run, or drove our cars, or went really fast in the same direction, then we could stop it, but then as soon as we stop pushing the earth backwards and stop, therefore, pushing it forwards again, it would regain speed. I think...

Actually F = m * (dV/dt)
So the force depends on how much time you apply it. The change in the earth's rotation speed would depend of how much time the ppl were walking / running.

Also, its impossible, because the relative masses of all those people is practically nothing compared to the mass of the earth. We could slow it down, but just slightly so that we might be a minute faster (or slower) every year or something.

So basicly is just a matter of how much time will be needed...

One q: Why would you wan't to stop the earth from rotating?

I don't want to stop the earth, just to know if it is posible or not =)

 

[Clements]

When our Sun becomes a red giant when its supply of hydrogen (to fuel its fusion reations) runs low, the earth will be destroyed as it is enveloped by the Sun, so technically then it will stop spinning, because it will no longer be a planet. But fear not, this won't happen for billions of years

I agree to stop the spin of the Earth, you need a force that equals the gravitational forces that keep it spinning. People walking is nowhere near going to do this, but an asteroid impact could also alter the Earth's rotation.

The formula F=Gm1m2/r^2 is the only formula I know that could calulate the force required, but I'm only an amateur physicist, so its probably more involved with even more factors to take into consideration. Gravity is the weakest of the fundemental forces, but acts over an infinite range, so any number of bodies in space can be affecting the Earth's rotation.