rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 752 ONLINE 20 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]891 viewsPOST REPLY
MTA Hobbies . Model Rectifier Corp . Heli Wholesaler

.
.
Off Topics > Diggin a hole
 
 
Andy R
Senior Heliman
Location: nowhere at the moment

Just a quick question:

If you were to dig a hole strait down and came out the other side of the earth, what would happen if you jumped in that hole??

would you fall out the other side??

would you stop in the middle??

and if someone jumped in the hole from the other end where would they pass???


(just a bit bored and cant figure it out, These are the days when I need to fly)
)




Andy R
10-21-2003 Over year old.
HOMEPAGE  
 
 
ChicoNick
Heliman
Location: Chico CA

I learned this in physics last year. If I remember correctly ( I could be wrong, and I don't feel like figuring it out for sure), it would take about 45 min. to reach the other side. Gravity would act like a spring and you would bounce back and fourth from one site to another until you eventualy come to rest at the center of the earth.

Nick
10-21-2003 Over year old.
 
 
James Yeram
Veteran
Location: Ridgecrest, CA

YOU WOULD DIE.
HOT MAGMA???
10-21-2003 Over year old.
 
 
zoro
Senior Heliman
Location: Darwin, Australia

or give me 1 MILLION Dollars. only a million???
10-21-2003 Over year old.
 
 
wmueller10
Heliman
Location: Ft Benning Area

(:
10-21-2003 Over year old.
 
 
ChicoNick
Heliman
Location: Chico CA

I believe it was 45 minutes was without wind resistance. This was a year ago so I might be wrong

Nick
10-22-2003 Over year old.
 
 
11290
Senior Heliman
Location: USA

You'ed be so tired from digging the hole you wouldn't really care.
10-22-2003 Over year old.
 
 
wmueller10
Heliman
Location: Ft Benning Area

(:
10-22-2003 Over year old.
 
 
RotorX
Key Veteran
Location: London

Why not just get a plane, , alot eaiser,i hear there are deals going on direct flights
10-22-2003 Over year old.
 
 
42GPW
Heliman
Location: North Royalton, Ohio

Re-think those estimates

This for the physics types out there... You cannot use the standard computation for time distance as the acceleration factor will be modified by the variability of the gravity as you travel through your tunnel. That is, as you "fall" though the tunnel, the mass producing the gravity force will be gradually decreasing as the force behind you in increasing.

I think you would, eventually find that with wind resistance (and there would be SOME) you would find yourself stuck in the middle of the earth, weightless after some initial ping-ponging before coming to rest in equilibrium.

Whatever, I'm going to go back and hit the bong a few more times and think about it.
10-22-2003 Over year old.
HOMEPAGE  
 
 
Andy R
Senior Heliman
Location: nowhere at the moment

Ok thanks for the answers so far just to make it a bit more interesting what about if one person jumped in the hole at opposite ends;

When would they meet??

would it be the middle if one was heavier than the other??



Does anyone really care???





Andy R
10-22-2003 Over year old.
HOMEPAGE  
 
 
daren
Veteran
Location: Hampshire Sponsored by Quick UK

Also how do we know there's gravity at the centre of the earth it might only be a couple of miles down

Daren
Using the ground to reverse engineer
10-22-2003 Over year old.
HOMEPAGE  
 
 
heliVoY
Veteran
Location: NJ

well, this gets interesting, gravity = matter bending space. You weigh what you weigh because you are being pulled into a spacial distortion (hole) created by the mass of the earth. The earth is bellow, so you are constantl in the tendency of falling downward towards the earths mass...

now ! if you are in the middle of the earth, and asuming there is no presure on you from the soruondings, and the presure is lets say the same as on the surface .. (including the air that would be in this tunnel, as hundreds of miles of air would exert quite some pressure on you ... )

well, heres what im getting at ... you would be pulled apart by the same ammount of gravity that pulls you down when on the surface .. , hmmm that would be weird ... gravity would still apply, it always does in the presence of any matter, except it would be pulling from all directions, and not from underneath .... (this might give you a headache )



Wojtek
10-22-2003 Over year old.
 
 
wmueller10
Heliman
Location: Ft Benning Area

(:
10-23-2003 Over year old.
 
 
ChicoNick
Heliman
Location: Chico CA

So I was off by 18.6 minutes. Well, I was kind of close. As I said I wasn't in the mood for figrin' it out for my self. I don't know if any one reading this has seen the Discovery Channel program where they have a machine that can create a magnetic field strong enough to float small objects including frogs, spiders and other small objects. I believe in this situation the objects are being pulled by the field. I am not sure if at the center of the earth you would be pulled to a single point at the center, or pulled equaly to the mass of the earth around you. I would tend to agree with rc*ag*aircraft, and that you would be pulled to a single point. Either way I dont think the force would be enough to cause a physical problem to your body. Once again, I retain the right to be mistaken

Nick
10-23-2003 Over year old.
 
 
heliVoY
Veteran
Location: NJ

gravity and magnetic force are 2 diferent things as i understand it, or at the very least, we still don't know for sure ?


Wojtek
10-23-2003 Over year old.
 
 
rover
Senior Heliman
Location: Brandon,FL

By the way to find the exact time would be somewhat difficult, you can not use constant acceleration equations such as:
s=1/2at² or (Vf)²-(Vi)²=2a(s) because the acceleration varies from the center of mass. The acceleration is only 9.81m/s² on the earths surface.
The equation for the acceleration due to gravity is derived from Newtons Law of Universal gravitation. g = GM/d²
TO figure the exact time would only be done by (dV)/dt or
(d² x)/dt² . You must use the time derivative of velocity to figure out the exact time. this is of course neglecting air resistance.


Quote 
gravity and magnetic force are 2 diferent things as i understand it, or at the very least, we still don't know for sure ?

Actually they are very similar, They are a force! Though the equations to derive either are very different
Magnetisim: F=qvXb or F=qvbsin(è)
Gravity: F=G*(Mm)/d²

Quote 
Also how do we know there's gravity at the centre of the earth it might only be a couple of miles down

Well that is simple. Every mass in the universe has an attraction to eachother according to Newtons Law of Universal Gravitation. What they are talking about is the center of mass. The center of mass can be figured by taking a system of the moments of all the masses relative to the center of mass.

Rover
Mechanical Engineer
10-23-2003 Over year old.
HOMEPAGE  
 
 
wmueller10
Heliman
Location: Ft Benning Area

(:
10-24-2003 Over year old.
 
 
rover
Senior Heliman
Location: Brandon,FL

rc*ag*aircraft,
It is not as simple as that, the taveling at 32.15ft/s². First off, that is an acceleration, the acceleration increases as you get closer to the center of mass. So it is a VARIABLE acceleration so you must use the dV/dt formula. It is only 32.15ft/s² at the surface of the earth. The acceleration also depends on the angle of inclination from the equator. Ok first off here is how i look at the problem, As an engineer we are taught to look at problems analyticaly.
1. acceleration varies with distance from center of mass. So as you approach the mass you are pulled faster and faster. Have you ever heard what would happen as you approach a singularity of a black hole? If you were upright your feet would be pulled faster than your head causing a strech on your body. essentially the same thing is happening on earth but to a lesser degree

2. the constant acceleration equations which are mentioned by various people above do not work for this problem, you must use the general form of acceleration which is dV/dt or d²x/dt². all of the constant acceleration equations are 'derived' from these seperable differential equations.

3. in order to solve this problem you have to take essentially the difference in accleration from the earths surface to the center of mass.

Anomaly , say when you are at the center of the Earth, in this hole, the rest of the earth besides just the center is still pulling on you, so there is still one more factor to take into effect, EF, sum of all forces by every particle on the earth since the earth does not have uniform mass distribution.

As you can see this is a complicated matter


Rover
Mechanical Engineer
10-24-2003 Over year old.
HOMEPAGE  
 
 
wmueller10
Heliman
Location: Ft Benning Area

(:
10-25-2003 Over year old.
 
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]891 viewsPOST REPLY
3D Heli Depot . JR-Spektrum . Gyro Hobbies

.
.
Off Topics > Diggin a hole
 PRINT TOPIC Advertisers 

Subscribe to This Topic

Wednesday, December 3 - 9:30 pm - Copyright © 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie