How fast does the earth need to rotate to realize 0 gravity?

[spidey07]

Originally posted by: dighn
sorry I wasn't being clear. I was actually agreeing with you 😛

anyway what am I doing here, I have work to do 😛

Do share!!!!

You're on a roll.

 

[BD2003]

Originally posted by: DrPizza

Originally posted by: spidey07
This seems really dumb, but could be fun.

Just how fast does the earth need to rotate before we effectively feel zero gravity?

I'm guessing it would have to be infinite because gravity doesn't change, it's always there. How much to reduce gravity's affect by 1 M/s^2?

Actually, it's not really dumb. That question comes up nearly every time I work on circular motion with students.

I must be missing something here - I can see how centripital force can create artificial gravity - walking *inside* a rotating torus etc.

But because the earth is a sphere (essentially), since the center of gravity is the center of the earth, how could rotation of the earth have any effect on the gravity at it's surface?

Is it essentially that the force of the rotation which would throw us off the earth (would it?), would be exactly equal to the force of gravity pulling us back down?

 

[her209]

Originally posted by: BD2003
Is it essentially that the force of the rotation which would throw us off the earth (would it?), would be exactly equal to the force of gravity pulling us back down?

Yes. But if you were to jump, i, accelerate yourself upwards, the centripital would cease to act on you and gravity would pull you back down.

 

[spidey07]

Originally posted by: her209

Originally posted by: BD2003
Is it essentially that the force of the rotation which would throw us off the earth (would it?), would be exactly equal to the force of gravity pulling us back down?

Yes. But if you were to jump, i, accelerate yourself upwards, the centripital would cease to act on you and gravity would pull you back down.

I don't think so.

Gravity is contolled by distance. You just accelerated yourself in a zero G situation away from the earth. You are now out of orbit and would toss and turn away from earth's gravity. Sure her gravity is still pulling you, but you have overcome it. -edit- well, provided that whole damn atmosphere thing wasn't there.

But then people can position a satellite to remain geosychronus using math. Amazaing really. A perpetually falling sattelite that just so happens to remain motionless with respect to the surface of the earth.

 

[Stiganator]

Pretty sure gravity comes from the >>>>mass of the earth (remember spacetime bedsheet thing with the marble) , not its angular velocity. If you're talking about centripetal acceleration that takes a good number of rotations per second. Since the earth only works at 1/day that means with would have to spin pretty fast. And it wouldn't decrease gravity, but would seem to enhance it? Assuming we are connected to earth. I suppose if you weren't connected then some pretty rad stuff could happen. Kind of a lot to take into consideration. I wish that spintron thing at the fair would do 0 G!

DISCLAIMER: I could be full of rubbish though, I'm not a physics ace! Feel free to correct me.

 

[TanisHalfElven]

Originally posted by: spidey07
This seems really dumb, but could be fun.

Just how fast does the earth need to rotate before we effectively feel zero gravity?

I'm guessing it would have to be infinite because gravity doesn't change, it's always there. How much to reduce gravity's affect by 1 M/s^2?

pretty easily. its basic physics learned in high school.
it has something to do with the rotating fast enough so all the gravitational force is required to provide the centripetal force needed to keep us moving in the circular path.

i have been out of touch with physics for 6 months so i don't exact remember the formulas of the top of my head.

 

[dighn]

Originally posted by: spidey07
Do share!!!!

You're on a roll.

it was fun 🙂

 

[spidey07]

Originally posted by: dighn

Originally posted by: spidey07
Do share!!!!

You're on a roll.

it was fun 🙂

Awwww....c'mon. It's a pub if you will.

This is fun. Nobody "owning" anybody. Nobody slamming. Just some fun conversation that I'm sure most of us have only a slight clue as to what we're talking about.

The original question is answered.....now lay the other affects.

 

[her209]

Originally posted by: spidey07

Originally posted by: her209

Originally posted by: BD2003
Is it essentially that the force of the rotation which would throw us off the earth (would it?), would be exactly equal to the force of gravity pulling us back down?

Yes. But if you were to jump, i, accelerate yourself upwards, the centripital would cease to act on you and gravity would pull you back down.

I don't think so.

Gravity is contolled by distance. You just accelerated yourself in a zero G situation away from the earth. You are now out of orbit and would toss and turn away from earth's gravity. Sure her gravity is still pulling you, but you have overcome it. -edit- well, provided that whole damn atmosphere thing wasn't there.

But then people can position a satellite to remain geosychronus using math. Amazaing really. A perpetually falling sattelite that just so happens to remain motionless with respect to the surface of the earth.

Yes, gravity varies based on distance. But the moment you lift off the ground, ie, no contact between your feet and the Earth, you are being accelerated at 9.8 m/s/s towards the Earth. In order to fly away from the Earth, you have to generate more than 9.8 m/s/s away from the Earth to counteract the gravitational pull.

 

[dighn]

Originally posted by: her209

Originally posted by: spidey07

Originally posted by: her209

Originally posted by: BD2003
Is it essentially that the force of the rotation which would throw us off the earth (would it?), would be exactly equal to the force of gravity pulling us back down?

Yes. But if you were to jump, i, accelerate yourself upwards, the centripital would cease to act on you and gravity would pull you back down.

I don't think so.

Gravity is contolled by distance. You just accelerated yourself in a zero G situation away from the earth. You are now out of orbit and would toss and turn away from earth's gravity. Sure her gravity is still pulling you, but you have overcome it. -edit- well, provided that whole damn atmosphere thing wasn't there.

But then people can position a satellite to remain geosychronus using math. Amazaing really. A perpetually falling sattelite that just so happens to remain motionless with respect to the surface of the earth.

Yes, gravity varies based on distance. But the moment you lift off the ground, ie, no contact between your feet and the Earth, you are being accelerated at 9.8 m/s/s towards the Earth. In order to fly away from the Earth, you have to generate more than 9.8 m/s/s away from the Earth to counteract the gravitational pull.

if you were already in "orbit" at ground, pushing away from earth would still preserve your original velocity. the balance would be upset and you would probably resettle at a higher orbit.

 

[YOyoYOhowsDAjello]

Originally posted by: dighn
sorry I wasn't being clear. I was actually agreeing with you 😛

anyway what am I doing here, I have work to do 😛

Oh, I know 😀

 

[her209]

Originally posted by: dighn

Originally posted by: her209

Originally posted by: spidey07

Originally posted by: her209

Originally posted by: BD2003
Is it essentially that the force of the rotation which would throw us off the earth (would it?), would be exactly equal to the force of gravity pulling us back down?

Yes. But if you were to jump, i, accelerate yourself upwards, the centripital would cease to act on you and gravity would pull you back down.

I don't think so.

Gravity is contolled by distance. You just accelerated yourself in a zero G situation away from the earth. You are now out of orbit and would toss and turn away from earth's gravity. Sure her gravity is still pulling you, but you have overcome it. -edit- well, provided that whole damn atmosphere thing wasn't there.

But then people can position a satellite to remain geosychronus using math. Amazaing really. A perpetually falling sattelite that just so happens to remain motionless with respect to the surface of the earth.

Yes, gravity varies based on distance. But the moment you lift off the ground, ie, no contact between your feet and the Earth, you are being accelerated at 9.8 m/s/s towards the Earth. In order to fly away from the Earth, you have to generate more than 9.8 m/s/s away from the Earth to counteract the gravitational pull.

if you were already in "orbit" at ground, pushing away from earth would still preserve your original velocity. the balance would be upset and you would probably resettle at a higher orbit.

Yes, you were in "orbit" at ground level. This is because you have two forces acting on you. Gravity pulling you towards the Earth and the centripital force throwing you off the Earth. The two forces counteract each other and cancel each other resulting in zero gravity. Once you push yourself off the Earth, ie, no longer in contact with the Earth, the centripital force disappears and you are pulled back down due to the Earth's gravitation. Can you jump higher? Yes, because you are accelerated right after you push off the Earth, but your velocity quickly diminishes after that.

 

[YOyoYOhowsDAjello]

Originally posted by: spidey07

Originally posted by: YOyoYOhowsDAjello
http://www2.jpl.nasa.gov/galileo/jupiter/core.html ?

So basically we have no freaking clue what jupiter composition is?

Me? I wanna visit Neptune. That's a cool freakin' place. Storms, blackhole drive, people coming back from said blackhole drive being psychos. Good stuff. Maybe they should make a movie out of it....kinda a sci-fi horrer flick.

Not for another 40 years 😉

 

[dighn]

Originally posted by: her209
Yes, you were in "orbit" at ground level. This is because you have two forces acting on you. Gravity pulling you towards the Earth and the centripital force throwing you off the Earth. The two forces counteract each other and cancel each other resulting in zero gravity. Once you push yourself off the Earth, ie, no longer in contact with the Earth, the centripital force disappears and you are pulled back down due to the Earth's gravitation. Can you jump higher? Yes, because you are accelerated right after you push off the Earth, but your velocity quickly diminishes after that.

but when fall, your velocity increases which should increase your orbit because the centripetal acceleration needed to remain at the previous orbit would be greater.

 

[her209]

Originally posted by: dighn

Originally posted by: her209
Yes, you were in "orbit" at ground level. This is because you have two forces acting on you. Gravity pulling you towards the Earth and the centripital force throwing you off the Earth. The two forces counteract each other and cancel each other resulting in zero gravity. Once you push yourself off the Earth, ie, no longer in contact with the Earth, the centripital force disappears and you are pulled back down due to the Earth's gravitation. Can you jump higher? Yes, because you are accelerated right after you push off the Earth, but your velocity quickly diminishes after that.

but when fall, your velocity increases which should increase your orbit because the centripetal acceleration needed to remain at the previous orbit would be greater.

Huh? What do you mean by the bolded section?

 

[dighn]

sorry what I meant is, if the velocity is increased, then you would need more centripetal force to keep it in circular motion, otherwise you'll fly off a little until your speed is reduced enough to settle at a higher orbit. anyway if you input any energy into it, you should end up at a higher orbit if you remain in one at all

anyway I"m not too sure about all this. something to work out later