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Stats: 1300995 members, 1849547 topics. Date: Monday, 26 January 2015 at 09:23 AM
|Re: Physics Graduates: Lets Meet Here by chamber2(m): 8:57am On Dec 31, 2011|
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.
|Re: Physics Graduates: Lets Meet Here by AjanleKoko: 9:39am On Dec 31, 2011|
But it is a real physics problem.
|Re: Physics Graduates: Lets Meet Here by yamakuza: 9:45am On Dec 31, 2011|
^ i wonder why they r quiet.
I predict at least 5 GBAGAUNS anywayz.
|Re: Physics Graduates: Lets Meet Here by chamber2(m): 9:57am On Dec 31, 2011|
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.
|Re: Physics Graduates: Lets Meet Here by AjanleKoko: 10:29am On Dec 31, 2011|
Even secondary school physics is enough to answer this question.
|Re: Physics Graduates: Lets Meet Here by Temayo: 12:44pm On Dec 31, 2011|
@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.
|Re: Physics Graduates: Lets Meet Here by yamakuza: 12:49pm On Dec 31, 2011|
^ did you guys do Theoretical Physics?
If Einstein and Lorentz thought this way, we'd still be using steam engines.
|Re: Physics Graduates: Lets Meet Here by AjanleKoko: 2:21pm On Dec 31, 2011|
See my post again below:
Come on guys, give it a go.
|Re: Physics Graduates: Lets Meet Here by sleekcm(m): 7:48pm On Dec 31, 2011|
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
|Re: Physics Graduates: Lets Meet Here by yamakuza: 7:53pm On Dec 31, 2011|
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?
|Re: Physics Graduates: Lets Meet Here by samlads: 7:24pm On Jan 01, 2012|
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 email@example.com a thoussndmiles start with a step.thank you.
|Re: Physics Graduates: Lets Meet Here by lekside44(m): 9:57am On Jan 02, 2012|
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.
|Re: Physics Graduates: Lets Meet Here by lekside44(m): 10:06am On Jan 02, 2012|
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.
|Re: Physics Graduates: Lets Meet Here by lekside44(m): 10:14am On Jan 02, 2012|
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?
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
|Re: Physics Graduates: Lets Meet Here by yamakuza: 10:33am On Jan 02, 2012|
^ by their fruits you shall know them.
|Re: Physics Graduates: Lets Meet Here by sleekcm(m): 9:57pm On Jan 02, 2012|
Weightlessness! Shlda remembered that. Another pop quiz mod.
|Re: Physics Graduates: Lets Meet Here by yamakuza: 10:05pm On Jan 02, 2012|
Hint: You will need lambda and 2 other standard values to solve the question in post 18.
|Re: Physics Graduates: Lets Meet Here by Pi0neer: 10:10am On Jan 03, 2012|
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
|Re: Physics Graduates: Lets Meet Here by yamakuza: 11:11am On Jan 03, 2012|
^ 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?
|Re: Physics Graduates: Lets Meet Here by Pi0neer: 11:35am On Jan 03, 2012|
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.
|Re: Physics Graduates: Lets Meet Here by yamakuza: 11:46am On Jan 03, 2012|
^ 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?
|Re: Physics Graduates: Lets Meet Here by Pi0neer: 11:57am On Jan 03, 2012|
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.
|Re: Physics Graduates: Lets Meet Here by yamakuza: 12:11pm On Jan 03, 2012|
^ thats at the surface, no?
I assume that at the centre, r = 0, so the actual solution is
Since we are assuming, am i free to assume that a 'black hole' exists at the centre of this tunnel?
|Re: Physics Graduates: Lets Meet Here by AjanleKoko: 12:46pm On Jan 03, 2012|
Good effort, and in principle correct.
Are you a physicist?
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 .
|Re: Physics Graduates: Lets Meet Here by yamakuza: 1:17pm On Jan 03, 2012|
Quite interesting, i must say!
|Re: Physics Graduates: Lets Meet Here by AjanleKoko: 2:30pm On Jan 03, 2012|
This Naija tire me.
Everybody is busy speaking grammar. Even physicists sef.
|Re: Physics Graduates: Lets Meet Here by lekside44(m): 2:41pm On Jan 03, 2012|
Pi0neer: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.
|Re: Physics Graduates: Lets Meet Here by SEFAGO(m): 2:50pm On Jan 03, 2012|
I know right!!! Aren't Faecesist supposed to express everything with models and equations not grammarticology
|Re: Physics Graduates: Lets Meet Here by sleekcm(m): 9:41am On Jan 04, 2012|
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
|Re: Physics Graduates: Lets Meet Here by yamakuza: 10:32am On Jan 04, 2012|
Hint: u'll also need the wavelenghts of red and green lights.
|Re: Physics Graduates: Lets Meet Here by sleekcm(m): 12:12pm On Jan 04, 2012|
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?
|Re: Physics Graduates: Lets Meet Here by yamakuza: 2:18pm On Jan 04, 2012|
Final Hint: At sufficient speed, red light will turn to green light.
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