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# Tag Archives: time

## Zeno’s paradox of Achilles and the tortoise

Can you please explain Zeno’s paradox Achilles and the tortoise, well i have read about it in many websites and books but i don’t completely understand it.

Achilles and the tortoise paradox is one of the four paradoxes collectively known as

The statement of  Achilles and the tortoise paradox goes like this:

“A fleet-of-foot Achilles is unable to catch a plodding tortoise which has been given a head start, since during the time it takes Achilles to catch up to a given position, the tortoise has moved forward some distance.”

But the above paradoxical statement is not real. It will of course make us think and many may tend to agree with that.

A detailed explanation was found at the link below

The story tells that the tortoise argued with Achilles that, if given a head start, He will never be able to overtake him. He argued on the lines and convinced the Achilles and He  agreed to the argument.

Consider a lamp, with a switch. Hit the switch once, it turns it on. Hit it again, it turns it off. Let us imagine there is a being with supernatural powers who likes to play with this lamp as follows. First, he turns it on. At the end of one minute, he turns it off. At the end of half a minute, he turns it on again. At the end of a quarter of a minute, he turns it off. In one eighth of a minute, he turns it on again. And so on, hitting the switch each time after waiting exactly one-half the time he waited before hitting it the last time. Applying the above discussion, it is easy to see that all these infinitely many time intervals add up to exactly two minutes.

QUESTION: At the end of two minutes, is the lamp on, or off?

ANOTHER QUESTION: Here the lamp started out being off. Would it have made any difference if it had started out being on?

Think it over!!!

Question: In Michio Kaku’s book Parallel Universes, it addresses the infinite possibility of a “time river” in correlation with Time Travel and its respective paradoxes. The one is question would be the grandfather paradox, in which if one would travel back in time and dispatch their parents his own future would would be “impossible”.

It has been suggested than not unlike a fork in the river, his own sequence of events that portray his future would remain unaffected rather the action would invoke a split or fork in the river to extend a parallel future to which he did not exist. Can you please prescribe further insight to this conundrum and any further literature on this subject would be much appreciated. For reference this is discussed on the last 4-5 pages of Chapter 5 in the book.

## Gravity and something more

Some Things That I Have Always Wondered OF : (i hope it may be answered soon …)
1)is it possible that our human body can withstand pressures twice or more than the atmospheric pressure without a suite or is there any artificial instruments or means in which our heart can be made to pump into a level in which we can attain this ability !!!
2)when more gravity  is experienced , it is said that time travels slowly – is it  relative ??? caz time goes at a constant rate !!! it is only the position or view that makes the observer feel the situations ???
3) Is there any gravity chambers successfully made out … in which the gravity can be changed accordingly to observe diff. phenomena ??? Cant It be possible to do that ????

Ans:

To be posted soon.

However, I agree that I may not be able to give you a satisfying answer to all your queries, as “Science says the first word of everything and the last word of nothing.” We are learning new things everyday. When we explore more and more, we find that we know less and less and our knowledge is too meagre.

By the time I prepare a well fitting answer to this, visitors are also requested to respond to the question by posting answers and comments.

## why in all the system of units time is always in second?

Please tell me why in all the system of units time is always in second? -Pankaj Sharma

## A Few Questions from Previous Board Papers and Answers Posted by Bright students

(A request to all students who have finished revising Physics; Now it’s time to practice Previous Question papers and sample papers. Practice to finish the questions within the stipulated time and with perfection)

Solved paper

## Space Time

What is space time?

Ans:

In order to describe an event, we need to specify its position in space and the time of occurrence. A four-dimensional continuum with the three co ordinates of space and time as the fourth co ordinate is called space-time.

Can you say What’s This?

## Questions waiting to be answered

What are LED lamps and what is there advantage over other lamps?

Superconductors are those substances that conduct  electricity without any resistance, so why cant we use them in transmitting electricity?

i want to know more about Loop quantum gravity and tz implications on gravity, time, space and how will it change our perspective on big bang???????

The magnets of earphones are of opposite polarities at left and right ears.why?

Why do we see the same face of moon always?

what is big bang?had it really happened?if it did,where is the proof?is it correct to say that earth and other celestial bodies were formed of this process?

Why does masses attract each other even though they are separated by even vacuum ?

why does the earth’s magnetic field flip?

Is it possible to travel back in time using a time machine and interact with the people who lived in that period?

1.Is there any body on this universe known to man which is purely frictionless?
2.Is it true that light travels in the same(relative to us) speed even if we are going away from or towards it?Is this proved by experiments and is this phenomena the basis for time travel?

Sir, I have learnt that the black hole finally opens into a white hole. If it is so, then how much distance would the objects attracted by the black hole travel, before they come out through the white hole?

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