Time Definition and 1000 Threads

I am very interested in quantum mechanics/physics and i keep seeing the Heisenberg uncertainty principle and its making me think about other forms of viewing particles. We traditionally use Photons to view something (our eyes), or other forms of radiation/particles, but i know that merely...

a tank is filled with water up to its brim a hole was made at the bottom of tank find time taken to empty tank if water flows at rate of 2h kg/s where h is height of liquid column and is equal to 20m radius is equal to h/2 [Moderator's note: moved from a technical forum.]

Here is my working in case it helps :)Ignore the v = 0.6/0.0001 = 6000m/s

This the answer key:: im confused because it say "how much energy has been dissipated after 5s". So shouldn't you be looking at the ground after 5 sec. but apparently the solution look at it before 5 sec, am I missing anything, can someone explain

Daylight saving will be permanent starting in 2023 according to the national news on PBS TV: https://www.pbs.org/newshour/nation/senate-unanimously-approves-bill-to-make-daylight-saving-time-permanent. The bipartisan bill, named the Sunshine Protection Act, would ensure Americans would no...

I am going to etch some titanium and need to mix up a 100ml batch of Kroll's reagent ( 92ml distilled water, 6ml nitric acid and 2ml hydrofluoric acid. Do I add the nitric acid to the water first and then add the hydrofluoric or vice-versa?

hello, i have some diffuculties with this problem, there's the point where the spring is attached to the rod and according to the equation of time period of physical pendulum , h represent the distance from the COM and the pivot point. here the pivot point is at the COM. and i know that it can't...

We think of length and time as the first fundamental quantities and velocity as the first derived quantity but any two determine the third so we would be completely justified in defining velocity as a fundamental quantity and one of length or time as the other, with the remaining being the first...

this is how i try to solve it: can someone please help me with that because i don't know what I am doing worng here.

Hi, I think this is a simple question, but I just wanted to ask how I could go about showing this in a scientific manner. I will try to use an analogy later on which is, I hope, a simple way to understand what I am doing. What I am trying to do: I am trying to investigate whether the...

A nuclear reactor is built to fuse two hydrogen atoms that are already ionized to protons. However, the electric field of the protons are becoming a significant obstacle. If the reaction was to be defined as H2--> 2H++2e-, if the mass of a proton is mp, the radius of a proton r the charge of an...

Hi, It's not a homework but still thought to post it here as advised in the past. A rocket is going to leave Earth's surface and it is decided that a data pulse encoding emission time of pulse will be sent every second from Earth station to the rocket, and the rocket would do the same. The...

Given a wavefunction ψ(x, 0) of a free particle at initial time t=0, I need to write the general expression of the function at time t. I used a Fourier transform of ψ(x, t) in terms of ψ(p, t), but, i don't understand how to use green's functions and the time dependent schrodinger equation to...

Vertical components: dy = 0m ay = 9.8m/s^2 [down] t = 1.34s V1y = required V2y = 0 i first tried to find V1y dy =vi t + 1/2 a t^2 and got V1y = -6.566 then i solved for time of flight dy =vi t + 1/2 a t^2 0 = -6.566t + 4/9t^2 and for 1.34 seconds does this mean the time of flight is the...

As I understand it, photons are subject to the same time and space distortions under SR as anything else, which is why they don't perceive time or space, since they travel at the speed of light. To an outside observer, then, they should appear stationary, immobile at their moment of creation...

This is still a confusing concept for me. The Lorentz transformation for proper time is expressed as tau = (1-v sq/c sq)^1/2 x coordinate time. Now we are told that tau is an invariant quantity with respect to all moving reference frames. So how can tau be invariant if its value depends on v...

Been studying Special Relativity in Uni. and I've noticed that all examples of relativistic motion provided are motions only along a single axis, like the one below: The particle's Reference Frame is moving only along the X axis in the example above. In this case the Lorentz Transformation for...

Question about time dilation. What if two clocks used the same reference frame? For instance, 2 countdown clocks using a particular pulsar as a measure of time. One stays here, the other is sent 100 million miles away at a very high velocity. Would they still reach 000 at the same time?

Here's my list of variables and things to account for: m=100kg Wnc=5000J Wfriction=-500J -Kinetic energy will be doubled (though I don't know how that plays into it exactly) -I don't think there's any PE because it's on level ground My idea of what the equation might be: Wnc +1/2mv^2initial =...

A week ago I accepted to review a paper for a top journal. I was contacted because I've published several papers on the same semi-obscure topic in the last two years. I accepted because the abstract was interesting and thought provoking. However, after having access to the full paper I...

Ion traps are very complex, but one of my Physics Olympiad textbooks presents a simplified model of a resonating charged particle in an ion trap A tuned circuit consists of an inductor and a parallel plate capacitor (capacitance C and plate separation d). It has a resonating frequency ##\nu...

Why does massive objects like stars and black holes slows time

I recently trying to learn General Relativity by first scraping the surface on ScienceClic's general relativity playlist, and then I stumbled upon a video where it said that we actually move through spacetime on a constant speed of c, and then I remember about time dilation because how speed on...

Water heater has the effect 2kW and is filled with 2kg water, with a heat capacity of 4,18Kj. The water needs to be warmed from 300K to 400K. How much time does it take for it to warm up? I've tried to solve this, but it seems that i need to know the heat capacity of the water heater, which i...

As of today, there are plenty of time machine mathematical models based on general relativity theory (warp drives, wormholes), but few ones based on quantum physics. However, back in 2010, Seth Lloyd wrote: "quantum mechanics supports a variety of counter-intuitive phenomena which might allow...

F.B.D Of first block (I have shown only the horizontal Forces) f1(max) = μ (1kg)(g) = 0.5 * 10 = 5N F.B.D Of the second Block f2(max) = μ (3kg)(g) = 15N Now the string will become taut and the tension will start acting when f = t = 5N But for 0<f<5N there will be no motion between the 1 kg...

Before starting, I will leave the link to the article I am talking about here: http://www.msc.univ-paris-diderot.fr/~phyexp/uploads/LaimantParesseux/aimant2.pdf I am conducting a similar experiment to the one discussed in the paper above. Basically, I am rolling a neodium supermagnet down a...

Is it because the current applied to a capacitor will never be time independent? Please help me out🙏

My attempt : ##\frac{\vec Ft^2}{2}=m\vec s## ##s=\frac{Ft^2}{2m}## ##P=\frac{W}{t}## ##k=\frac{\vec F\cdot \vec s}{t}## ##k=\frac{F^2t^2}{2mt}## ##k=\frac{F^2t}{2m}## ##F=\sqrt{\frac{2mk}{t}}## But there was an option which was ##2\sqrt{\frac{mk}{t}}##. And my assumption was that it was...

Is there a view in quantummechanics, of quantummechanics, without time as a concept?

Hello. It's my current understanding that dark energy is causing the universe's expansion to accelerate. It's also my current understanding that there is some mechanism that caused dark energy's effects to become more pronounced, several billion years ago. Which makes me wonder if the value...

Firstly, how is time complexity of BFS $O(b^d)$. Say I have this tree with goal n, how do I calculate time complexity for it? Assume left to right traversal. I know the answer is a,b,c,x1,d,e,f,i,j,k,g,h,z,l,m,n. But I am not sure how to calculate time complexity here using the above formula

If all the matter was condensed to a single point at the beginning of the universe, then why didn't it all collapse into a black hole? I have heard speculation that the laws of physics change with time, is this the reason why there was no black hole at the beginning or is the reason more...

At the very beginning, I accept that I have a faulty mouse. I bought it last year, and it's been only one year (almost), and the left button is malfunctioning. Single clicks are often becoming double clicks, which is causing a host of problems — closing two tabs one after the other in browsers...

I calculated the time for the velocity before ground impact, which is v = -189.23 and the velocity at end of engine burn time, which is 120.996. I also calculated the max altitude (y = 1826.94), and the time to reach the max altitude was t = 23.0823 seconds. So from this information, I did: t =...

Assuming it’s one body whose initial speed is u. First it attains height h then H. t1 and t2 are two times at which they attain h and H. ##h=ut1-\frac12gt1^2## ##H=ut2-\frac12gt2^2## ##\frac {t1}{t2}=1/3## Replacing t2 with 3t1, I am stuck.

Lets consider T(\vec{p})=\frac{\vec{p}^2}{2m}=\frac{\vec{p}\cdot \vec{p}}{2m}. Then \frac{dT}{dt}=\vec{v}\cdot \vec{F}. And if we consider T=\frac{p^2}{2m} than \frac{dT}{dt}=\frac{1}{2m}2p\frac{dp}{dt} Could I see from that somehow that this is \vec{v}\cdot \vec{F}?

I just started learning about Special Relativity and have come upon the topics of Time dilation and Length contraction. Its a bit abstract for me and I just want to cross ref my knowledge here and see if someone can tell me if I am understanding this correctly. I've attached an excerpt of a...

Wolfgang Pauli's matrices are $$\sigma_x=\begin{bmatrix}0& 1\\1 & 0\end{bmatrix},\quad \sigma_y=\begin{bmatrix}0& -i\\i & 0\end{bmatrix},\quad \sigma_z=\begin{bmatrix}1& 0\\0 & -1\end{bmatrix}$$ He introduces these equations as "the equations of motion" of the spin in a magnetic field. $$...

I am working on a new application and am trying to figure out how I can calculate the cooling rate of Steel. I have a load of Steel Tubes. 1200lb total mass. Tubes have some variance on size depending on what is being run on a given day, but nominally, we are looking at 1" OD x .1875" Wall x...

If a person was rotating on a verticle axis from head to toe like the Earth or quasar. If nothing can go faster than light, from the person's perspective looking at the stars traveling across the night sky, if you increase the rotation of the earth, stars further than a certain critical distance...

how does the first step use mean value theorem? I don't get it , can anyone explain , thanks.

$$y=2 A \cos 2 \pi\left(\frac{\nu_{1}-\nu_{2}}{2}\right) t \sin 2 \pi\left(\frac{\nu_{1}+\nu_{2}}{2}\right) t$$ Can you explain me the significance of the above equation in the context of waves and oscillations? It's something to do with 'beats,'.

I have been trying to find a time lapse animation showing lunar libration made of actual real photographs of the Moon. However, no matter how much I search, I can only find computer-rendered animations. Does anybody know of a video made out of actual photographs of the real thing?

I had a lamp that was good for 10 years but two years ago it was burnt out, I replaced it and in this two years we have a naughty kid playing with it, it is burnt out recently again. Is it likely due to his behavior (switch it ON and OFF within short time) or quality of light bulb in recent...

how long does it take a 12.5 kg gold bar to melting at 3000 degree C°? Why does the water coming out of the waterjet slow down after a while?

I am confused. My understanding is that proper time is used in 4 vectors analysis because proper time is frame invariant. Every other inertial frame will agree on the same time increment if they use the proper time of that one reference frame. But when you do the Lorentz transformation, the...

In a stressful situation, when you're thinking rapidly, time really does seem to slow down. Like "that was the longest 30 seconds of my life." Since thinking is made up of the firing of action potentials in neurons, could those events, in the brain, work with relativity to slow down personal...

I don't understand why my solution is wrong. Here is my solution. $$ r_{\theta} = R\cos{\theta} \vec{i} + R\sin{\theta} \vec{j} $$ $$ v_{\theta} = v\cos(\theta + \frac{\pi}{2}) \vec{i} + v\sin(\theta + \frac{\pi}{2}) \vec{j} $$ $$ p_{\theta} = mvR(-\sin{\theta}) \vec{i} +mvR(\cos{\theta}...

How to Judge original time and original length of special relativity