AJ

if you drill a hole right in the centre of the earth and then jump into the hole, i am sure you will find yourself in another planet other than earth   Maybe Mars

But from your statement it's obvious you didn't drill any hole. So, you won't come out any where.

chamber2:

AJ

if you drill a hole right in the centre of the earth and then jump into the hole, i am sure you will find yourself in another planet other than earth   Maybe Mars

But from your statement it's obvious you didn't drill any hole. So, you won't come out any where.

Nice try
But it is a real physics problem.

^ i wonder why they r quiet.

I predict at least 5 GBAGAUNS anywayz.

I am not a physical scientist.

Na commonsense i use.

Abeg let the scientist in the house answer this question na.

Where is T22? I am suspecting Economics stole him.

Even secondary school physics is enough to answer this question.

@Ajanlekoko, that's a very funny and unrealistic question you know? Let's start this way, the earth is not a perfect sphere that's why the radius of the earth is an approximate value. Also the core of the earth is not solid but molten as a result of its high temperature and it is the responsible factor of the gravitational effect of the earth. If its possible you found your way pass the centre of the earth you can still not reach another planet but rather another continent if not ocean depending on your longitude and latitude. In general, i want to say i really like your question for its practical nature.

^ did you guys do Theoretical Physics?

If Einstein and Lorentz thought this way, we'd still be using steam engines.

Temayo:

@Ajanlekoko, that's a very funny and unrealistic question you know? Let's start this way, the earth is not a perfect sphere that's why the radius of the earth is an approximate value. Also the core of the earth is not solid but molten as a result of its high temperature and it is the responsible factor of the gravitational effect of the earth. If its possible you found your way pass the centre of the earth you can still not reach another planet but rather another continent if not ocean depending on your longitude and latitude. In general, i want to say i really like your question for its practical nature.

Ogbeni,
See my post again below:

AjanleKoko:

Physics pop quiz:

The earth is spherical, right?
What would happen if I drilled a hole right through the center of the earth, from the surface of where I am, to come out somewhere else? And then jumped into the hole.
Assume the earth has a cold core and no ground water or anything like that. Just rock. What would happen?

Come on guys, give it a go.

You would probably hit your head several times against the rocky interior. The oxygen level wld decrease proportionately with depth even as gravity pulls u towards d centre. Sorry but u won't make it to the other side. Hence, Insufficient oxygen+ head injuries + cold = certain death. Q.E.D

sleekcm:

You would probably hit your head several times against the rocky interior. The oxygen level wld decrease proportionately with depth even as gravity pulls u towards d centre. Sorry but u won't make it to the other side. Hence, Insufficient oxygen+ head injuries + cold = certain death. Q.E.D

what would happen to your body, or anything thrown into that hole?


If i drop a pen into that hole, would it get to the other side?

am so excited reading through. am a pure and applied physicist '09. presently i am practsing electronics.i design,construct and implement electronics projects such as automatic power change over,automatic gen power on and shutdown, unintirrupted power supply that most regards as inverter and etc.am also into electrical surface and conduit wirring. my major concern in this career is not about d grads but abt d one's yet in school who doesnt have a compass of this course cos iwas once like them back in the days only waiting cert after certain years in institutions before imet a GOD sent.am not also a gurru anyway,am still learning,but i crave today for what i call NIGERIAN PHYSICS/ELECTRICAL ELECTRONICS VILLAGE where you and i can come together and shear knowledge to build abetter tomorrow,abetter naija. remember government cannever and will never be able to do everything for you and i.you can reach me through samladonline@yahoo.co.uk a thoussndmiles start with a step.thank you.

GREATEST PHYSICISTS, NICE YOU GUYS ARE MEETING HERE. PHYSICS ACTUALLY IS A COURSE THAT UNLOCK THE SECRET OF NATURE. IT IS HOWEVER SAD THAT NIGERIA IS NEVER IN THAT RACE. AMERICA AND OTHER ADVANCED COUNTRIES HAVE LEARN FROM THE WORLD WARS THAT SCIENCE, PARTICULARLY PHYSICS CAN WIN WARS. THIS WARS A LESSON WE ALL SEE WITH JAPAN SURRENDERING UNCONDITIONALLY JUST AFTER THREE DAYS OF THE SECOND ATOMIC BOMB WAS DROPPED, A WAR THAT WOULD HAVE LASTED MORE THAN A YEAR AFTER. AFTER THE WAR, THE AMERICAN GOVERNMENT GAVE GRANTS TO SCHOOLS (AND PHYSICISTS) TO UNLOCK MORE OF SUCH NATURES. THESE CRATED JOBS FOR THE PHYSICISTS AND INCREASED MANS KNOWLEDGE BEYOND LIMITS. ORDINARILY THE PHYSICIST JOB IS LIKE THAT OF A PRIEST. A PRIEST LEAVES ON THE TITHE AND OFFERING OF MEMBERS. IN ADVANCED COUNTRIES, THESE GRANTS CREATED MANY JOBS AND THUS WEALTH IN MANY HIGH PROFILE PLACE LIKE NASA, INTERNATIONAL ATOMIC AGENCY, ETC. IN NIGERIA HOWEVER, THE CLASSROOM IS THE SUREST PLACE FOR A PHYSICIST. THANK GOD HOWEVER, BANKS, TELECOM INDUSTRIES, MINISTRIES AND SOME OTHER FINANCIAL INDUSTRIES ARE CREATING JOB OPPORTUNITIES. SO NEVER GET TO WORRY.

bukkytroni:

, If you see the Quantitative Methods and Portfolio Management, its all pure mathematics and physics. You will use poisson distribution, correlation, regression, skewness, kurtosis, confidence interval, variance, standard deviation AND pure calculus etc to Model returns and risk of an investment and summarize what a stock, porfolio or investment will look like in future.

It was very very very very interesting for me because I had a fully quantitative background and eventually turned to a lecture among my finance peers because IF YOU WERE NEVER A PHYSICIST (ANALYTICAL), YOU CAN NEVER BE/THINK LIKE A PHYSICIST.

I am very proud that I studied physics and If given the opportunity to go to university again, I will definitely do a double major in PHYSICS/ACTUARIAL SCIENCE/QUANTITATIVE FINANCE.

Meanwhile, I work with a firm where I crunch all their data and tell them in simple sentences what the figures and trends are saying,

WELL YOU HAVE ACTUALLY DONE SOME APPLIED PHYSICS. I HAVE A BOOK WHICH I AM WORKING ON WITH THE TITLE MONEY CIRCUITRY. IT INVOLVES THE APPLICATION OF PHYSIC LAWS IN EXPLAINING FINANCIAL ACTIVITIES.
BUT MY GREATEST PROBLEM IS THAT FINANCIAL LAWS AND THEORIES CANT WORK IN NIGERIA.

FROM AJANLEKOKO

Physics pop quiz:

The earth is spherical, right?
What would happen if I drilled a hole right through the center of the earth, from the surface of where I am, to come out somewhere else? And then jumped into the hole.
Assume the earth has a cold core and no ground water or anything like that. Just rock. What would happen?

Reply

WELL, YOU CANNOT PASS THROUGH BECAUSE AT THE CENTER OF THE EARTH YOU WILL EXPERIENCE ZERO GRAVITY AND FLOAT AS IF YOU ARE IN SPACE

^ by their fruits you shall know them.

Weightlessness! Shlda remembered that. Another pop quiz mod.

Hint: You will need lambda and 2 other standard values to solve the question in post 18.

lekside44:

FROM AJANLEKOKO

Physics pop quiz:

The earth is spherical, right?
What would happen if I drilled a hole right through the center of the earth, from the surface of where I am, to come out somewhere else? And then jumped into the hole.
Assume the earth has a cold core and no ground water or anything like that. Just rock. What would happen?

Reply

WELL, YOU CANNOT PASS THROUGH BECAUSE AT THE CENTER OF THE EARTH YOU WILL EXPERIENCE ZERO GRAVITY AND FLOAT AS IF YOU ARE IN SPACE

Bros, remember that you would have picked up acceleration while falling, and it will increase as you approach the center, so you get lighter and move faster.
I think you will be weightless, but still accelerating, so you will move past the point of zero gravity and continue to accelerate towards the surface. Gravity will start to act again, and you will get heavier as you move towards the surface, eventually causing a gradual deceleration. You will most likely fall back into the hole at some point, and start the whole process again. Effectively, you'll be oscillating back and forth between surfaces.

Mods, I hope I try small

^ u try small, and e wan make sense, but i no agree.

Your argument would imply that based on the masses of the objects, some would make it out of the hole, some to the surface and others not to the surface before reversing direction?

yamakuza:

^ u try small, and e wan make sense, but i no agree.

Your argument would imply that based on the masses of the objects, some would make it out of the hole, some to the surface and others not to the surface before reversing direction?

Not at all sir.
What I am saying is, no object would make it out of the hole. It would be an oscillation. In a vacuum, the oscillation will be for an infinite duration. But given air resistance and other factors, the object will travel less and less distance in both directions till it finally settles at the center of the earth.

Gravity means you fall 9.8meters per square second. When you jump into the hole, you accelerate at that speed, when you cross the center, you also decelerate at that speed. Esentially, you can setup a virtual 'pendulum' in this way.

^ sounds perfect!

Perpetual Motion?

So, essentially, if we both jumped in at opposite ends, we would go past each other several times before finally settling at the center?

One more thing, if g (or is it G?) was 0 at the centre then F would automatically be 0 once the objects reached the center and they would just hang there, right?

Any luck with the question in Post #18?

Pi0neer:

Bros, remember that you would have picked up acceleration while falling, and it will increase as you approach the center, so you get lighter and move faster.
I think you will be weightless, but still accelerating, so you will move past the point of zero gravity and continue to accelerate towards the surface. Gravity will start to act again, and you will get heavier as you move towards the surface, eventually causing a gradual deceleration. You will most likely fall back into the hole at some point, and start the whole process again. Effectively, you'll be oscillating back and forth between surfaces.

Mods, I hope I try small

yamakuza:

^ sounds perfect!

So, essentially, if we both jumped in at opposite ends, we would go past each other several times before finally settling at the center?

One more thing, if g (or is it G?) was 0 at the centre then F would automatically be 0 once the objects reached the center and they would just hang there, right?

Any luck with the question in Post #18?

It's a bit more complicated than that, sir.

You have to look at Kepler's equation, which is f = GmM/r^2, where the earth's mass is the big M and you are the small M. G is the gravitational constant of 6.673x10^-11, and r is the distance between the surface and the center.

On the earth's surface, the acceleration due to gravity is 9.81m/s^2. the F in Kepler's equation is the acceleration you will gain when you fall towards the center.

Galileo demonstrated the fact that different objects of different masses will fall at the same speed in the famous leaning tower of pisa experiment.

^ thats at the surface, no?

I assume that at the centre, r = 0, so the actual solution is indeterminate undefined?

Since we are assuming, am i free to assume that a 'black hole' exists at the centre of this tunnel?

Pi0neer:

Bros, remember that you would have picked up acceleration while falling, and it will increase as you approach the center, so you get lighter and move faster.
I think you will be weightless, but still accelerating, so you will move past the point of zero gravity and continue to accelerate towards the surface. Gravity will start to act again, and you will get heavier as you move towards the surface, eventually causing a gradual deceleration. You will most likely fall back into the hole at some point, and start the whole process again. Effectively, you'll be oscillating back and forth between surfaces.

Mods, I hope I try small

Good effort, and in principle correct.
Are you a physicist?

yamakuza:

^ thats at the surface, no?

I assume that at the centre, r = 0, so the actual solution is indeterminate?

Since we are assuming, am i free to assume that a 'black hole' exists at the centre of this tunnel?

Not a 'black hole', though the similarity is very close.
What Pi0neer didn't explain in his post, was that you need to assume that the density of the planet must be assumed to be the same at all points.
Essentially a 'perfect sphere', with all points on the surface equidistant from the center.

Regarding the actual motion, the earth's mass is pulling you down and causing you to accelerate, so by the time you get to the center, you would have achieved maximum acceleration. That will take you past the earth's center and towards the surface. Once you cross that center, you immediately begin to decelerate, until you get to zero speed just at the surface. Then you start to fall again.

This concept has been severally proven mathematically, and is referred to as the 'gravity train'. You can check here: http://en.wikipedia.org/wiki/Gravity_train for some details. There are also mathematical proofs all over the Internet.

Our physicists no dey try o , kudos to Pi0neer for at least giving it a crack .

Quite interesting, i must say!

^^
This Naija tire me.
Everybody is busy speaking grammar. Even physicists sef.

Pi0neer:

Bros, remember that you would have picked up acceleration while falling, and it will increase as you approach the center, so you get lighter and move faster.
I think you will be weightless, but still accelerating, so you will move past the point of zero gravity and continue to accelerate towards the surface. Gravity will start to act again, and you will get heavier as you move towards the surface, eventually causing a gradual deceleration. You will most likely fall back into the hole at some point, and start the whole process again. Effectively, you'll be oscillating back and forth between surfaces.

Mods, I hope I try small

acceleration due to gravity does not increase while you start moving into the earth, rather, it starts decreasing. the acceleration of gravity on you at those points is the summation of all the NEWTONS gravitational forces of all atoms that makes up the planet which is action on you at that point in time.

I totally agreed with you that you will oscillate back and forth within the earth crust. i had never taught of these before, not even while i was in school. actually, this is different from a black hole whose escape velocity is greater than the speed of light.
when you start traveling inside the earth, kelpers law is slightly modified thus given the reduction in gravitational pull.

AjanleKoko:

^^
This Naija tire me.
Everybody is busy speaking grammar. Even physicists sef.

I know right!!! Aren't Faecesist supposed to express everything with models and equations not grammarticology

A drunk driver was arrested for beating traffic lights. He claimed that he saw green as he approached the stop lights. At what speed would he have been travelling for his assertion to be true?



lambda (λ)= c/f where, c=v= speed of light= constant= 3x10^8 m/s, f= frequency= 1/T (/s)

Since we are looking for his speed, c, at least one of the other two variables should be known.
But we have two unknowns!There is no frame of reference ( position). I can't help but think we have to apply The Relativity Theory here.

If the speed of light is the same for all inertial observers regardless of the state of motion of the source, its logical to assume that the man was traveling at the same speed of 3x10^8 m/s

sleekcm:

A drunk driver was arrested for beating traffic lights. He claimed that he saw green as he approached the stop lights. At what speed would he have been travelling for his assertion to be true?



lambda (λ)= c/f where, c=v= speed of light= constant= 3x10^8 m/s, f= frequency= 1/T (/s)

Since we are looking for his speed, c, at least one of the other two variables should be known.
But we have two unknowns!There is no frame of reference ( position). I can't help but think we have to apply The Relativity Theory here.

If the speed of light is the same for all inertial observers regardless of the state of motion of the source, its logical to assume that the man was traveling at the same speed of 3x10^8 m/s

Hint: u'll also need the wavelenghts of red and green lights.

Okay.The Visible Light Spectrum
Color Wavelength (nm)
Red 625 - 740
Orange 590 - 625
Yellow 565 - 590
Green 520 - 565
Cyan 500 - 520
Blue 435 - 500
Violet 380 - 435. Assume, Wavelength (Red)= 625nm
Wavelength (Green)= 565nm
lambda (λ) = wavelength (Red)+ wavelength (Green)= (625+565)nm = 1190nm = 1.19 E -6 Meters
Now we have, λ= 1.19 E-6 m= his and c = 3x10^8 m/s, f= 3 E 8/ 0.00000119 (ms^2) when u plug in this value into c= λf u still get a value of 3x10^8 m/s, no?

sleekcm:

Okay.The Visible Light Spectrum
Color Wavelength (nm)
Red 625 - 740
Orange 590 - 625
Yellow 565 - 590
Green 520 - 565
Cyan 500 - 520
Blue 435 - 500
Violet 380 - 435. Assume, Wavelength (Red)= 625nm
Wavelength (Green)= 565nm
lambda (λ) = wavelength (Red)+ wavelength (Green)= (625+565)nm = 1190nm = 1.19 E -6 Meters
Now we have, λ= 1.19 E-6 m= his and c = 3x10^8 m/s, f= 3 E 8/ 0.00000119 (ms^2) when u plug in this value into c= λf u still get a value of 3x10^8 m/s, no?

Final Hint: At sufficient speed, red light will turn to green light.