/sci/ - Science & Math

But she's not. The center of the earth is the center of gravity. The only way you'd be right would be if your momentum from the original fall rocketed you all the way through.

Your wife assumes air resistance. If so, I am free to assume that you can't actually dig such a hole in the first place. Once you start admitting exceptions and caveats, there's no clear end.

Punch her in the face and declare your joy at victory.

assuming no air resistance or other external forces, you would exit the other side with the same velocity as you went in with, this is due to gravity being a function of mass, and an equal amount of mass being on either side of the centre of the earth

She's right, you're wrong. 100% efficiency does not exist.

>>4217433
I said ignoring air resistance. I don't think that's a hard think to ignore considering the question is "if there was a tunnel running through the center of the earth". With nothing to slow you down, your acceleration to the center would be equal to your acceleration from the center. There would be no terminal velocity to limit you on your way down.

>assuming no air resistance
You might as well assume that you're a unicorn.

>>4217440
She's assuming that there's a fucking tunnel running through the earth for this question.

>>4217434
>>4217436
it's not just air resistance - some of your kinetic energy transfers to heat and vibration. Even without air resistance, OP's wife is still right. You'd go back and forth with an ever-decreasing range of motion until your kinetic energy reached 0.

>>4217443
>Heat and vibration
That's due to air resistance fuckface

>>4217448

this, you're dumb. faggot dot head. jk i love browns.

>>4217448
no sir. Kinetic energy transfers to heat and vibration within the moving body even without air resistance.

>>4217442
So you went ahead and threw another impossible assumption on top of it. That's not how thought experiments work, you get one assumption and then play by the rules from there. If you allow yourself unlimited assumptions, you might as well throw in unicorns and the philosopher's stone.

>>4217463
It's a hypothetical question, not a fucking experiment.

>>4217463

if you had a high enough initial velocity, the external forces wont be sufficient to stop you from reaching the other side, though the threshold velocity will be pretty high, due to the diameter of the earth being pretty large

1st Law: The best you can do it break even (eternal oscillation).

2nd Law: You can't break even.

WELP.

>>4217421
Once you fall past the crust, the temperature of the tunnel would be that of the molten magma surrounding it. The water in your body would vaporize long before you ever got close to the core.

By bringing up the question, your wife is implying that you should go burn to death horribly in the pits of Hell. And, given your responses to your original post, I can see why.

OP is being trolled hard in this thread.

@OP, obviously you are correct. If by no air resistance, you are saying there is no loss of energy, then yes you would oscillate back and forth from each side of the planet forever.

bump

>Please tell her she is wrong.

You're wrong, bitch. Now go make OP a sandwich.

You would hit the walls all the time because your spinning velocity in the beginning is faster than earths.

She's right. You would end up in eternal oscilation. I think the period of the oscilation is about 84 minutes.

if there was absolutely no resistance, and the earth was a perfectly symmetrical spheroid, you're right. Realistically you'd be pulled off to one side, and not get all the way back on the other side. Eventually you'd stop in the centre and slowly drift to whichever side of the tube exerted a stronger pull

>>4219862
That's a good point, but it would be negligible as the force of gravitation would adjust to pull you and you'd only have some residual momentum in the leading direction.

=[
Well, i think she's right. You can''t fall into the other side of the tunnel, up on the other side of the earth crust. Nothing can propel such a movement. That would mean, beyond the centre of the earth you would accelerate towards the other side of the tunnel, against the pull of gravity. And assuming the same motion, you would basically fall on the other side of the tunnel, which is impossible to do against gravity. You would settle in the middle after going a bit further than the centre of the tunnel.

considering that any ficticious forces you felt would be symmetric, you would fall straight through under the force of gravity, accelerating you in the first half by an amount equivalent to your deceleration in the second half.

>>4219888
Nice trips.

To get from the centre to the surface you need the same amount of force as you'd gain from going from the surface to the centre. Conveniently you get this force from falling, and would be carried by it up the other end.
>>4219889
Only assuming you managed to fall straight down the middle, which you wouldn't. Any contact with the sides and you wouldn't make it out the other.

>>4219892

We're assuming frictionless, although contact with the sides introduces a normal force (because of coriolis and aimuthal effects), it would be the same on the way down and on the way up, meaning that the work done bringing you to the center of the earth is the same as the negative work done bringing you away from it. Remember work done is always in the direction of motion.

>>4219902
But you're travelling in the same direction for the whole fall.

youtube.com/watch?v=wuHau1LTH8Y

you're wife has teh autismal

>>4219908

Okay, pick one, ficticious forces or inertial reference frame.

The problem is easier in the former, but in an intertial frame, the earth's spinning and your changing radius of rotation need to be taken into account messily.

In the (non-inertial) frame of the earth, you experience ficticious forces.

In both cases, everything you feel is symmetric going in and coming out. Any force you exert on the wall is present in both directions and doesn't incur a frictional forces.

You fall "straight" through and reach the other end.

Anyone who makes any simplifications, such as no air resistance, is trying to pick out specific parts of a situation. I'm assuming here that OP wants to know what happens if you fall through the centre of a large sphere with mass of the Earth. So why are we talking about pressures and temperatures? They're irrelevant.

Also, OP is probably a clever troll. This kind of question is typical of what fucks /sci/ up.