# swaha

Senior Members

159

1. ## proof of uncertainity principle without using braket vectors

Is there any proof of the uncertainity principle without the use of braket vectors? If so please send me where to find it.
2. ## <Infinite Mass> = <Absolute Vacuum> Properties

black hole i think has infinite density not infinite mass as volume becomes zero.
3. ## Bullets, Distance and acting forces

i didnt get the question. was it how long the fastest bullet can travel in air? then i think the answer would depend on 1. gravity. 2. centrifugal force. 3. air resistance. 4. latitude for we would need the velocity of earth also.
4. ## in proving a beta gamma relation.

B(m,n)=gamma(m).gamma(n)/gamma(m+n) while changing the variables x to rcosz, y=rsinz and taking their differentials we tactly assume the terms containing (dz)^2 & (dr)^2 terms vanish. we only consider terms containing dzdr in the double integral in place of dxdy can somebody please explain why (dz)^2 & (dr)^2 terms vanish or not considered for the double integral?
5. ## what was there?

if something expanda then it requires space outside. does it mean there is space outside universe also? atleast it must be when it was a point. for a point must be somewhere in space & expand to somewhere in space to occupy a volume.
6. ## how can u say that the universe is expanding?

whether the universe expands or the galaxies move away from each other at a greater speed of light the relative velocity remains greater than the speed of the light. does it mean the reference frame of those galaxies they are at our past?
7. ## can anybody suggest what should i do?

i am a 1st yr undergraduate student in physics honours. have interests in fields like relativity, quantum, cosmology physics. want to know about research oportunities for me in pg courses. any expert ideas will be appreciated. thank you.
8. ## Question about Special Relativity

what if the force is impulsive? no pushing case.
9. ## how can u say that the universe is expanding?

well since we are accelerating without something stopping us can some day we reah the speed of light?
10. ## how can u say that the universe is expanding?

gravitational energy is actually a bound state one so why universe needs to expand i really dont get it. 2 things can separate if some repulsive force exists else why move leaving the bound state? actualy the place i stay asking questions to teachers is almost a crime so i really dont get any help regarding what i want to know. pls explain it.
11. ## Time Dilation

why do you think there is a time dialation when they reach the same speed please explain?
12. ## how can u say that the universe is expanding?

is there any proof? actually gravitational force is attractive so it should be shrinking by the way if it had to. pls explain where i was wrong.
13. ## how can this happen?

ya. is there harm supposing what a light would observe? actually infinite no of times a person is allowed to see the event, just dont understand then y dont we really do???????????? Merged post follows: Consecutive posts mergedok lets forget about the reference frame moves at vel c.let it move with some uless than c. still there is the problem.
14. ## why is time called 4th dimension?

does it mean that L should vary with t2-t1 to keep S a constant?
15. ## what was there?

but the ballon was initially at a point. so where was the universe?
16. ## can anybody show me the proof of fourier series?

no. i dont care whaether it converges or not, for the time being atleast. what i wanted to know really was that if say f(x) is a function of period 2pi. then y is it supposed to be able to be written as linear combinations of functions of sines & cosines their angles being multiples of 2pi always? it's easy to understand the opposite way instead if there is a linear combination of sines & cosines of multiples of 2pi then the lcm of their periods become 2pi hence the combined function has the period 2pi. but our books state the 1st one regarding shm as fourier series. somebody
17. ## what was there?

what did u mean by that point was everywhere? a point must be somewhere located in space? Merged post follows: Consecutive posts mergednobody gave me any ballon idea. dont know what's it.
18. ## how was speed of light measured?

shouldnt the speed of light be zero wrt itself?
19. ## what do you observe?

how can the rest frame of something be unphysical which exists itself?
20. ## why is time called 4th dimension?

please define what is meant by S, L here.
21. ## can anybody show me the proof of fourier series?

well but he must have given a proof of the statement i suppose. i didnt find it anywhere.
22. ## why is time called 4th dimension?

ok thanks. let's focus on the problem now.
23. ## what was there?

how did matter appear then? was it stored somewhere probably as energy? did you mean the point enlarged to our universe? please explain. Merged post follows: Consecutive posts mergedwell again if our universe was a point then where was it?

25. ## why is time called 4th dimension?

The invariant quantity is the so called interval that includes time. In this sense it serves as a forth coordinate r4=i*ct in a four-dimentional space (r,i*ct But time also vaiers in different reference frames. wasnt it the light velocity that remained invariant? got confused again. help. Merged post follows: Consecutive posts mergedi beg ur pardon for i had to copy paste what mr bob has written. i dont know how to use this quoting stuff here. sorry.
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