A paradox is a logically self-contradictory statement or a statement that runs contrary to one's expectation. It is a statement that, despite apparently valid reasoning from true premises, leads to a seemingly self-contradictory or a logically unacceptable conclusion. A paradox usually involves contradictory-yet-interrelated elements that exist simultaneously and persist over time.In logic, many paradoxes exist which are known to be invalid arguments, but which are nevertheless valuable in promoting critical thinking, while other paradoxes have revealed errors in definitions which were assumed to be rigorous, and have caused axioms of mathematics and logic to be re-examined. One example is Russell's paradox, which questions whether a "list of all lists that do not contain themselves" would include itself, and showed that attempts to found set theory on the identification of sets with properties or predicates were flawed. Others, such as Curry's paradox, cannot be easily resolved by making foundational changes in a logical system.Examples outside logic include the ship of Theseus from philosophy, a paradox which questions whether a ship repaired over time by replacing each and all of its wooden parts, one at a time, would remain the same ship. Paradoxes can also take the form of images or other media. For example, M.C. Escher featured perspective-based paradoxes in many of his drawings, with walls that are regarded as floors from other points of view, and staircases that appear to climb endlessly.In common usage, the word "paradox" often refers to statements that are ironic or unexpected, such as "the paradox that standing is more tiring than walking".
Resolving the "Twin Paradox"
http://mentock.home.mindspring.com/twins.htm
I've been trying to follow this unusual explanation to resolve twin paradox, which uses the lorentz relativistic velocity transformation equation to get the speed bob zooms off after Ann at,15/17 C. I can understand...
I have read the sine rule:
It states-->
sin A/a=sin B/b=sin C/c = 1/2R
where R is circumradius.
Now,
a=2Rsin A
b=2Rsin B
c=2Rsin C
For a triangle R is fixed.
In an obtuse angled triangle, the side opposite largest angle is the longest(geomtrically)
But the sine of an obtuse angle...
Hi there, here I have this paradox and hope you can explain.
There are 2 charged particles, one is moving at speed v, one is stationary. We know the moving charge gives off a magnetic field which can not exert any force onto the other charge because it does not move.
Now assume we stay in a...
HI My question is what would the outcome be if the twins started out in 2 ships traveling at uniform .6c relative to Earth and one of them then took her ship and traveled to Earth and back?
Which twin would be older?
Reverse Twins paradox ?
This may have come up before but I haven't seen it and don't know the answer.
What if the twins started out in two ships moving together at relativistically significant velocity relative to earth. One of the twins then simply goes to Earth and back while the other...
I'm trying to make sense of the way time dimension is related to the other 3, the example is twin paradox:
Observer 1 is moving away at 0.866c from observer 2, who is standing still, then turns around at a defined point and goes back at the same speed, arriving back to observer 2 position...
The classic lighthouse thought experiment leads to a situation in which some "thing" is traveling faster than the speed of light. This is the case because the lighthouse's light beam, if powerful enough, will shine a circle of light on its destination that can travel faster than the speed of...
Homework Statement
Identical twins Speedo and Goslo join amigration from the Earth to Planet X. It is 20.0 light years away in a reference frame in which both planets are at rest. The twins, of the same age, depart at the same time on different spacecraft s. Speedo's craft travels steadily at...
The https://www.physicsforums.com/archive/index.php/t-240147.html" occurred to me several years ago when I was still chasing relativity by the tail. I didn't learn that Rietdijk, Putnam, and Penrose had advanced this argument till yesterday. Weird. Anyway there are direct testable consequences...
In trying to come up with an example in S.R., I came up with the following: 2 rockets, a distance d apart as measured in the Earth frame, each have a speed of 0.8c and are on a head on collision with the other. What is the time to impact as measured in the Earth frame and on one of the rockets...
URGENT! T and U paradox
Sorry I know I posted this already, but I realized that it isn't really introductory physics:
Homework Statement
I'm really confused about how I should do this problem and this is urgent so if anyone can help, it would be very much appreaciated. Thanks.
T and U...
URGENT! T and U paradox
Homework Statement
I'm really confused about how I should do this problem and this is urgent so if anyone can help, it would be very much appreaciated. Thanks.
T and U Bar paradox (This is my assigned homework, it is an edit of question 6-5 from a textbook called...
Hi Folks,
I am stuck at a certain logic problem which is probably very common and easy for undergrad compsci students so forgive me if my question seems rather trivial. The question is this:
1. I believe the statement "This statement is false" is not a proposition and is paradoxical in...
Easy to understand problem (please read; I promise you'll understand):
I've created my own financial spreadsheet. One of its functions is to allow me to automatically determine how much money I need to save every month m in order to accumulate x dollars in y amount of time.
Normally...
was original EPR paper (as written by Einstein) contradicted uncertainty principal or was it against the copenhegon interpretation of QM? please tell me any website where original EPR paradox is discussed.
It is my understanding that the twin paradox arose from the fully reciprocal nature of special theory which shows that if a clock is moving past me in outer space that clock is ticking over at a slower rate than my clock but that from the point of view of a person accompanying that clock it is...
Hi,
i thought of a paradox that I'm not sure i can resolve for myself.
You have a 1-dim potential well of length L. You measure a particle to be within x=L/2\pm \sigma with equal probability. Assume sigma is very tiny. After a short time \Delta t the wavefunction has evolved to be...
This thing is making me pull my hair out: http://en.wikipedia.org/wiki/Bertrand%27s_box_paradox Can someone give me a good explanation of this?
As for the Monty Hall Problem, I think I understand it. This is how I think of it: There is a 1/3 possibility of picking the correct door and 2/3...
I can't fully understand why a person who makes a journey into space in a high-speed rocket will return home to find his age less than an identical twin who stayed on Earth. It makes since for the twin who stayed on earth, but for the twin who traveled into space, he sees himself at rest and...
ok so this is kinda a silly idea i just came up with on the spot during math class because I am sure that like the rest of you on this forum, during high school 90% of math class was/is spent daydreaming because 90% of people need to be explained simple concepts a thousand times lol. so the...
Homework Statement
A very thin steel plate with a circular hole m
1 in diameter centered
on the y-axis lies parallel to the xz plane in frame S and moves in the +y
direction at a constant speed y
v (as illustrated in Figure 1-44 of the text).
A meterstick lying on the...
The classical paradigm of how an object acquires gravitational potential energy goes like this: First, we take the case where the object is near the surface of the Earth which we define as the zero reference point. The object has a mass of 1 kg. We lift the object by an agent, such as a hand...
hi,
recall the familiar round trip - it's more or less the same as in this arXiv article (http://arxiv.org/PS_cache/physics/pdf/0604/0604025v3.pdf) - round trip with acceleration g. me and my friends were wondering the following:
imagine that the passenger abroad the rocket travels for 4...
I have a question about the Twin Paradox. I don't know if I'm right or wrong, but that's why I figured I would come here to ask.
The way I understand things is that the twin on Earth's clock would end up being faster than the twin's clock out in deep space if the twin out in space was...
I have a paradox here. Please tell me what is wrong.
I need to prove that \lim_{x \rightarrow a-}f(x) = -\infty
f(x) = \frac{x}{(x-1)^2(x-3)}
1st case
For all M , where M is a arbitrary large number, there exists \delta>0 such that f(x)<M whenever 0 < a-x < \delta
0 < a-x < \delta...
SR says that as an object reaches the speed of light its mass approaches infinity. How can light reach the speed of light without having an infinite mass?
Thought experiment / story:
Albert the Alien sits atop a non-accelerating comet traveling 0.5c. He approaches earth, barely missing it, and passes on by. After he has passed Earth, he looks back toward it with his ultra-sensitive telescope and sees the face of Hyphy the Human. Hyphy the...
As I was reading Fabric of the Cosmos, I got stumped at the relativity of simultaneity section. This led me to Google for some additional explanation. I stumbled upon http://www.phys.unsw.edu.au/einsteinlight/jw/module4_pole_paradox.htm" which made me think of this question regarding the pole...
Einstein's resolution of the "clock paradox"
I have read that most physicists believe that Einstein's resolution of the "clock paradox" or "twins paradox" is flawed and just plain wrong. I'm curious about what everyone here thinks about it.
And I believe Einstein generally was interested in...
envelope paradox??
Maths can sometimes be nearly as interesting as physics...
There are two envelopes on a table. Both have cash in, you don't know how much but one has twice as much as the other
You can pick just one envelope, and you are allowed at most one swap.
You choose envelope A say...
If we can agree that a black hole can exist, and that its gravitational field is intensified with its mass, the we can also agree that its gravity can create one hell of a gravitational lens.
If that is the case, and EM radiation, whatever the frequency, is directed towards the black hole...
I may have discovered an explanation to the Zeno Paradox. However, in this explanation, the concept of a race between to objects at different speeds is simplified into one object traveling a given distance. The distance traveled in this example can be represented by the variable D. If the...
Problem
Imagine a wheel of radius R consisting of an outer rim of length 2\pi R and a set of spokes of length R connected to a central hub. If the wheel spins so fast that its rim is traveling at a significant fraction of c, the rim ought to contract to less than 2\pi R in length by length...
Hi all,
Physical law:
I understand the derivation of the Planck law for the blackbody spectrum and why it takes slightly different forms whether you are doing the analysis in the frequency domain or the wavelength domain. That is to say, you cannot simply invoke the Planck relation...
I take a certain journey and due to heavy traffic crawl along the first half of the complete distance of my journey at an average speed of 10 mph.
How fast would I have to travel over the second half of the journey to bring my average speed to 20 mph?
[This is Problem 10 on page 18 in...
Homework problem given by Count Iblis to the PF community:
Consider a box containing a pendulum of total mass M in a spacecraft that is in free falling motion. Suppose that the engines of the spacecraft are turned on and the spacecraft is accelerating at acceleration a, where a is...
Hi,
I have the following problem:
The formula for the Period of a classic pendulum is T=sqrt(L/g)
Where: T: Period of the Pendulum suspended on a string.
g: Earth's acceleration (=G*Mass_of_Earth/(Radius_of_Earth)^2
L: Length of the Pendulum String
Now, let us...
Wikipedia:
http://en.wikipedia.org/wiki/Rietdijk-Putnam_Argument
Quote:
"Two people pass each other on the street; and according to one of the two people, an Andromedean space fleet has already set off on its journey, while to the other, the decision as to whether or not the journey will...
Suppose i build a time machine , then go back in the past & kill myself . I die the instant i kill my past , but how in the first place i built the time machine ?
Take a look at this following paragraph that i wrote in another thread
"think of two rockets moving at each other under inertia at a course so that they pass very close. Observer A will look at both clocks when the rockets pass. he will see his own as being T and he will see observer B,s...
I am just a little bit unsure about something I read on the "twin paradox".
It talks about Dick and Jane who are twins, each 20yrs old. Dick departs at a speed of 0.80c to a star 20 light years away. So I'm sure you all know how the story goes, Dick is 50yrs old when he returns and Jane is 70...
So, I was thinking about a variation on the Twin Paradox, and was hoping someone could help me work through it. The motivation is the usual explanation for the Twin Paradox, namely that one twin accelerates and so breaks the symmetry. This begs the question of what happens when both twins ride...
[SOLVED] Twin Paradox problem
Here is a problem about twin paradox that I can't quite figure out. I got part a, but I can't get part b. I think that the 6 years spent doing research is kinda throwing me off. Help!
The International Space Federation constructs a new spaceship that can...
The laws of Coulomb versus Ampere and the electromagnetic Machian "paradox"
Here's an apparent paradox that has been tunneling about in my little mind lately. Maybe someone out there can help me with it.
Imagine if you will, a vast empty region of space devoid of any visible distant...
Suppose one twin travel to a distance L and turn around, another twin travel to a distance L/2 and turn around. When they reunite at home, the twin travel longer will age less?
Since they both experience acceleration, so acceleration is not the cause of age difference.
Can acceleration break...
suppose we have a stationary observer 'A' at the origin. at t=0 rockets 'B' and 'C' pass the origin moving at gamma=10 but rocket B stops. when rocket 'C' reaches some point along the x-axis rocket 'B' accelerates to gamma=10 as measured by rocket 'C'. when rockets 'B' and 'C' meet its over...
According to the Wikpedia entry
"[URL
and this paper http://www.aapps.org/archive/bulletin/vol14/14_1/14_1_p03p07.pdf
the conclusion reached by Bell in his paradox is still disputed even by some scientists today.
Since the linked articles give plenty of mathematical explanations I...
There's one of the paradoxes with SR that I've never actually seen an answer for.
There is a man on a train traveling at a velocity where length contraction starts to matter. Say, .3c. There are some dirty bandits that have rigged up a trap door system in a mountain up ahead on the tracks...