Time Definition and 1000 Threads

I don't have any solution

Hello! I am generating electrons from a 3D gaussian source. The electrons all have the same energy, but the direction is isotropic. The electron source is in between 2 plates that act as a capacitor, and one of them acts as a time of flight (tof) detector. I know the voltage on the plates very...

I'm fairly certain that the first one is marked correctly. Should the second one be where there are red marks or is it correct as it was marked previously? Any advice with graph reading?

Halves-lives and average lifetimes, when studying nuclear decay, are often expressed in years even though years are not standarized, at least in SI (as far as I know). Borrowing the convention from astronomy and astrophysics, I usually take 1 \mathrm{yr} to be equal to 365.25 days of 86400...

Hopefully the answer on this question is positive. This forum has a very good reference about the Experimental Basis of Special Relativity. The tests of the Twin Paradox conclude that faster moving clocks tick/run slower, however this seems to be an 'absolute' fact. They do not show symmetry or...

In the table of nuclides, it shows that Ag 108 can go through either electron capture or beta- decay (though the branching ratio for electron capture decay is much lower). What determines that? Do nuclides try to maximize binding energy or binding energy per nucleon? And is decay into Palladium...

Hello everyone! I was doing some dimensional analysis to find an equation that gives a acceleration as a function of time, using constant power. I came up with the equation $$a = k\sqrt {\frac P {mt}}$$ I differentiated velocity with respect to time in order to check my work and also checked out...

What determines the time between atomic absorption and emission of photons? Is there a correlation to blackbody radiation?

Hello, I'm not sure if this is the right place to post my question, however I still want to know. Recently, my teacher asked me the following question: "In which of the cases will the cooling time be the least: 1. the ball is suspended from the ceiling 2.the ball lies on a stand with a thermal...

Summary: Trying to differentiate with respect to ## \theta ## is entangling me in cos and sec terms. A simple problem I found, while looking for calculus practice. Roads between home and main road are 30 mph, main road is 60mph: What is the optimum ## \theta ## to minimise journey time? ## t...

THe question is pretty simple. I was doing an exercise, in which $$p = \lambda P, Q = \lambda q$$ is a canonical transformation. We can check it by $$\{Q,P \} = 1$$ But, if we add $$t' = \lambda ^2 t$$, the question says that the transformation is not canonical anymore. I am a little...

I've been trying some online projectile problems. Specifically, I was using this one on master difficulty, looking at row e. It uses a random number generator; I shared the data I received in the Homework Statement above. According to the help section, you can solve this with the formula...

hello i would like to get some help with this problem. At first it try to calculate the impulse by the area but i found it too difficult Then i try to solve it by the forumla J= F(t-t0), but the problem is that i don't know what F is so i try to solve it like this F10) = 8 F(33) = -13 so EF =...

I understand it's experimentally verified muons traveling at relativistic speeds relative to an observer will be observed to have longer half-life than would be observed in the rest frame of the muons, which is explained theoretically by a relativistic time dilation effect. Does this correspond...

According to a video I watched recently 'time' allegedly runs a tad slower in places on the Earth where the magnetic field is stronger. No doubt that has been tested and confirmed by atomic clock experiments.. to my simple mind that just suggests a timing error caused by the difference in...

let's say i would like to drop by one of my pals on a certain planet, 7ly away. I got to 42 years but it doesn't really sound correct.

Obviously, a third observer who is at rest with respect to the disk will see that the clock on the outside has a much faster velocity than a clock on the interior of the disk, so clearly the outside clock will show that it has measured less time. But that's one question. What about looking at...

I am looking for an equation that I can use to compute L/min or mL/min for a 480cc vessel going from 150bar to 250bar with a fill time of 6min. Sensors for flow rate at these pressures are hard to find, but I thought there might be a way to work this out with the parameters known. An equation...

I may be going to my storm shelter sometime in the early morning:

When we can use relation? \mbox{curl}(-\frac{\partial \vec{B}}{\partial t})=-\frac{\partial}{\partial t}\mbox{curl}\vec{B}

Not sure what I'm doing wrong... Problem: Sisters Helen and Anne live 332 miles apart. For Thanksgiving, they met at their other sister’s house partway between their homes. Helen drove 3.2 hours and Anne drove 2.8 hours. Helen’s average speed was four miles per hour faster than Anne’s. Find...

New member here; just a physics hobbyist. There is probably a simple answer to this question but I could not find it. We know time flows faster on mountaintops relative to sea level due to gravitational time dilation. Over millions of years, wouldn't there be a cumulative effect making the...

I was wondering if anyone could walk me though a better explanation on how to get the given results for these two questions. The solutions posted by my professor aren't really clear to me so if anyone is able to better explain how to get the solution it would be much appreciated!

From our local paper here in Brisbane yesterday (behind a paywall, so precis follows) 'Almost half the 35 Queenslanders who have contracted flurona since January 1 have been admitted to hospital. There have been 35 confirmed cases of people infected with both the Covid-19 and influenza viruses...

I found a website (link listed below) that gives date and time of the Winter Solstice of 1980. The date (12/21/1980). The time (UT 16:52). Being that the Sun stays in the same position for 3 days, what is the exact day & time it starts to move again? Anyone know where to find this information...

I'm quite aware that according to Einstein light is a particle and a wave at the same time. However, I try to imagine how exactly would light expand. A photon must likely have a certain timing for expansion. I mean, after a photon is originated it immedialy multiplies itself into many other...

These are all the chapters for introductory mechanics in my textbook. What I have been doing is reading the chapter then following it up with watching a tonne of lectures and worked examples on that topic and attempting to do the problems. I’m on Applying Newton’s laws and I’ve been studying it...

I have read that nothing in math makes time having more than 1 dimension impossible. But if time had 2 dimensions or even 3 dimensions on its own, what would that mean? Could time travel and time travel paradoxes be allowed without destroying the universe or creating branch realities? I think...

A science teacher ask if I could help one of her students build a "Time Dilation Clock" so, at launch the Ships chronometer and the local time are in sync. with a 3g continuous thrust, at some point the time, the time at the launch site will be going twice as fast as the ships chronometer. so...

I'm trying to make sure I understand how the traveling twin tracks the time of his stationary earthbound sibling and the time of another stationary observer who's farther away. From what I've understood until now, it's pretty straightforward with the earthbound twin: In the traveler's frame, the...

Homework Statement:: The SI definition of unit of time says the following. "The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom." Relevant Equations:: None I know an...

I apologize if this is a stupid question I just always thought length involves 2 points to have a length at different locations.

Hi! I want to start with saying that I'm not an expert on these type of problems, but I will be gratefull for some calarifications. I've heard that there's nothing in psysics that says that time travel is impossible. I want to make a case with the time traveling battery. Could be any mass with...

An interesting approach to those eavesdropping devices in your life. https://arxiv.org/pdf/2112.07076.pdf ABSTRACT Automatic speech recognition systems have created exciting possibilities for applications, however they also enable opportunities for systematic eavesdropping. We propose a method...

Is time travel possible in Newtonian curved spacetime?

I tried using the equation Q'*t= Q1+Q2. Where Q' is the energy of the reactor aka 200,000 kJ and t is the time. Take Q1 to be (1/2m*2257) and Q2 to be (1/2m*4.184*90). The 90 is the change in temperature for the phase change to occur from liquid water to gas, or boiling. Plugged everything in...

I'm struggling to wrap my head around the twin paradox in special relativity especially when dealing with multiple vectors. In my thought experiment say I have a set of twins. Both set out in opposite directions and intend to sling shot around two different black holes(luckily equidistant from...

Is it plausible to get the highest grade all the time when your IQ is the highest in your class when you try your hardest? One answer that I got for this question is "My experience in high school is that if you really have the highest IQ in the class, you’ll get the highest grades without...

Hello, I try to solve a time dependent problem described by a Hamiltonian of the type $$ \mathcal{H}(t) = H_0 + V \delta(t) .$$ I started by trying to solve the Schrödinger equation with ##H_0 = p^2 / 2m##, but I'm getting a bit stuck. I would like to know if you know of any books that deal...

I finished my 1st-year physics, took analysis, linear algebra, mathematical logic, classical mechanics, quantum mechanics(I was exempted from intro phy and took some 3rd-year physics courses) I internal transferred to pure maths. The reason is that the curriculum of the physics programme in our...

I am completely stuck on problem 2.45 of Blennow's book Mathematical Models for Physics and Engineering. @Orodruin It says "We just stated that the moment of inertia tensor ##I_{ij}## satisfies the relation$${\dot{I}}_{ij}\omega_j=\varepsilon_{ijk}\omega_jI_{kl}\omega_l$$Show that this relation...

Question: Galileo released a metal ball from rest so that it could roll down a smooth inclined plane. The time t taken to roll a distance s was measured. He repeated the experiment, each time recording the time taken to travel a different fraction of the distance s. Write an expression for the...

I've started reading Introduction to Quantum Mechanics by Griffiths and I encountered this proof that once normalized the solution of Schrodinger equation will always be normalized in future: And I am not 100% convinced to this proof. In 1.26 he states that ##\Psi^{*} \frac{\partial...

I derived the formula for t but don't know how it works Δt = p/F I got p = mv = 60*8 = 480kgms-1 Δt = 480/120N = 4s Is that correct?

If time travel were possible, could someone alter or set up the way they want things to happen before they went back to their desired destination?

Taking the variation w.r.t f(x) of the integral over some x domain of F[f(x), f'(x), df(x)/dt], why doesn't df(x)/dt need to be taken a variational derivative and is treated as if it were constant?

Needing Direction I have sets of number: week 9 27 turned in 25 good 2 bad = 93% & 7% week 10 56 turned in 55 good 1 bad = 98% & 2% week 11 75 turned in 74 good 1 bad = 99% & 1% week 12 6 turned in 5...

The transition probability -- the probability that a particle which started out in the state ##\psi_a## will be found, at time ##t##, in the state ##\psi_b## -- is $$P_{a \to b} = \frac{|V_{ab}|}{\hbar^2} \frac{sin^2[(\omega_0 - \omega)t/2]}{(\omega_0 - \omega^2}.$$ (Griffiths, Introduction...

At first, I inputted h(t), of which I solved for, into the mass flow rate formula. So it looked something like this, m-dot(t) = -(density)*[sqrt(g*(H-(g*d^4*t^2/D^4)]*(pi/4)*d^2 But I don't think that's right? Any thoughts?