Time Definition and 1000 Threads

Hello, When dealing with a dataframe with two columns, X and T where T is time, the time column is often converted to be the index of the dataframe itself (which by default is 0,1,2,3,...). What is the advantage of doing that? I know how to implement that but I am not sure what the main benefit...

Hi, I'm sizing motor for a linear motion, usually for the time distance graph would be looks like this, however, how does the graph look like if the stroke is very short? Example: velocity is 0.1m/s, acceleration is 1m/s2, moving stroke is 0.5mm, a cycle is within 0.05s the application is to...

Covers: - An investigation of consciousness - Microbiomes evolve with us - How life keeps time

I have seen this in pop-science, is it correct? Does antiparticles move in the oppisite direction of time? Is it possible to prove this experimentaly? Does it have any practical consequenses? We use PET-scaning everyday, is there anything to consider when working with positrones connected with...

In a conversation Dr. Stephen Hawking said that he used Imaginary time as a 4th dimension to show that there was nothing before the big bang. How is it possible for Imaginary Time to act as a fourth dimension when it is still part of the ordinary time dimension?

Hello, I was looking at my physics lab manual... There is a table reporting time and distance data which were both measured and collected (see below). My understanding is that the uncertainty for different and measured time instants should be the same because the time was measured with the same...

I understand that through process of elimination the only plausible solution is (E), but a question that rises up: When the ball bounces, does the velocity change from negative to positive instantly (as shown by the dotted lines) or gradually (a very small time period, but still solid line)?

Hi - I'm using the ASHRAE guide equation to determine the time to freeze an insulated pipe and im comparing the values they used to their published table as a guide and I seem to be off by the same value as the Rt value, and I dont think they have neglected the thermal resistance of the...

Are there any mathematical models which operate with physical time as with hypercomplex number? If yes, are there any related experiments?

Here is only my solution: ##A_1 \frac{\mathrm d h}{\mathrm d t}=-A_2\sqrt{2hg}##, so by integrating we get ##h(t)=\left(\sqrt{h_0}-\frac{A_2}{2A_1}\sqrt{2g} t\right)^2.## Setting ##h(T)=0## we get ##T=\frac{A_1}{A_2}\sqrt{\frac{2h_0}{g}}.## By doing the first time derivative of ##h## we...

Physicists suggesting that observing space objects will be in a time that passed the time you are doing the observation if that object is far enough to exceed the distance the light photons can travel in respect to time (300,000 km/sec), anybody can refer me to equation, study or science that...

I need to integrate time dilation with derivative, how could I do that?

I am currently studying Newton's laws and mechanics. I have this question: Why is distance=half a*t^2? Where did the 1/2 come from? Can someone explain this without using calculus?

initial velocity y component is (cos30) * 20. t = 25m / ((cos30) * 20)m/s = 1.45 seconds d = vt + .5at^2 v= 20sin30 v= 10 , d= 10(1.45s) + .5(-9.8m/s^s)(1.45s)^2 d=4.2m 4.2-2.5 = +1.7m, so the ball will not hit the fence I need confirmation please

Here is the definition of spacetime? “In physics, spacetime is any mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum.” But if space is literally the absence of matter or physical properties, and time has no...

I am writing to investigate a unique theoretical perspective that explores the relationship between time and the motion of celestial bodies, particularly focusing on Earth's trajectory through space. I posit that time, particularly in the past, is intricately connected to the precise path that a...

Model attached below. Changed Sarah's 65 mph to m/s and got 29 m/s. Sarah's initial position is positive. Her initial velocity is negative. Her acceleration is positive; Andrew's initial position is negative. His initial velocity is positive. His acceleration is negative. Graph is attached...

Hello! I try to understand how in different frames clocks tick and stop simultaneously but show different time? I suppose that velocity is reason of time dilation effect but I'm not sure. Thanks.

I considered example of time dilation with light clock. I have a question about measuring time in reference frame with clock. If we know that clock move from A to B in the reference frame with clock then what time of motion is measured in this reference frame? (In non-moving reference frame...

Data and graphs here (the time is measured every 1/30 of a second, but for some reason, Google Sheets thought 1/30 wasn't a number so its in decimals!!! very confusing!!! so sorry about that!). why is the slope only 4.68, should it not be 9.81m/s^2? is the slope of m/s^2 not supposed to be...

Regarding the new "quasar clock" data showing that time ran more slowly (~5-fold) shortly after the Big Bang: is it all based on the periodic variation in luminosity at various wavelengths of some quasars (and presumably explained by the special relativistic time dilation effect from "spatial...

If the veil stretches prefectly, then when the princess moves by ##\Delta x##, then if the spider was not moving, he would also move by ##\Delta x## from the door, so he would be in the same distance from the princess. So assuming it, the time would be ##t_f=\frac {l_0}{u}## but that is no...

We all know the four fundamental forces in physics: gravity, electromagnetism, and the strong and weak nuclear forces; and there is now some discussion about a fifth, more obscure force involving muons. But I have a question; could the fifth force be something we deal with every day? Could it...

I’m an absolute beginner and I need someone to show me where I’m wrong. Knowing the formula of acceleration ∆v (change in velocity) / ∆t (change in time) where ∆v = ∆x (distance) / ∆t, a common way of relating acceleration to distance is to say a (acceleration) = (distance/time)/time =...

Hi Everyone, Just a disclaimer, I'm not a physicist or a physics student, just a layperson with an interest in physics. So please forgive any lack of understanding on my part :). Anyway, I recently started trying to gain a better understand of what time is in the real world, because some...

I have probably a basic question from Space, Time and Matter area. My 11 years old daughter asked me once why we exist physically in a stable form if everything is infinite. We had a conversation about it but then it got me thinking about this and it seems I can't find the answer. There is...

Is entropy real? It seems like it's not real because it depends on how you group microstates together into a macrostate, and the way you group them can be arbitrary. For example (at 13:04 of the video below), there are 91,520 microstates in the macrostate “9 in left; 1 in right” but 627,264...

This is a tough question to phrase but I haven’t been able to find an answer yet, although I’m sure one exists. I’ll try expand what it is I’m asking. I’m no physicist but I think I have a general understanding of what they are saying when they describe a block space-time universe where the past...

I am a bit confused with velocities in this problem. From Philipp's view, the coin's initial velocity is zero, so its transfer kinetic energy is also zero. When I am standing on a non-moving ground, is the coin's initial velocity ##v## in direction the walkway is moving? But won't I get then...

I am aware that this question is very simple and basic. Using ##y(t)=y_0+v_{0,y}t-\frac {1}{2}gt^2## we can find distance as a function of time: ##|y_1-y_2|=|y_0+v_{0,y}t|=-y_0- v_{0,y}t## I assumed the downward direction to be negative. So as I wrote ##D(t)=-y_0- v_{0,y}t##. It tells that the...

Position and momentum are the popular pairs of properties with uncertainty we often hear about, for example that we cannot know with precision where an electron is and its momentum at the same time. What are others? Such as an example of an energy and a time that we cannot know both...

For this, Can someone please tell me why they integrate the impulse over from ##t_i## to ##t_f##? Why not from ##j_i## to ##j_f##? It seems strange integrating impulse with respect to time. Many thanks!

In Peskin P85: It says the Time-ordered exponential is just a notation，in my understanding, it means $$\begin{aligned} &T\left\{ \exp \left[ -i\int_{t_0}^t{d}t^{\prime}H_I\left( t^{\prime} \right) \right] \right\}\\ &\ne T\left\{ 1+(-i)\int_{t_0}^t{d}t_1H_I\left( t_1 \right)...

Hi, I am not sure if I have calculated the task b correctly. I always interpret an open switch as an infinitely large resistor, which is why no current is flowing through this "resistor". So there is no current in the red circle, as it was the case in task part a, but only in the blue circle...

After watching this clip Electric Field Lines Lab I wonder if it is possible to see both electric field lines and magnetic field lines at the same time by swapping the two nails in the video with two bar magnets, as the conductors as we understand bar magnets are metals and metals are good...

TL;DR Summary: Find acceleration of electron in dB/dt >0 Hello. Here is a problem that i'm not so sure about: Inside a solenoid there is a time-dipendent magnetic field B, so we have dB/dt = b (constant). We want to know the acceleration of an electron: a) placed in the center of the solenoid...

https://www.scientificamerican.com/article/is-time-travel-possible/

Sabine Hossenfelder says time dilation is due to acceleration in the twin's paradox. Is this true? At 12 minutes into this video , Hossenfelder states, "This is the real time dilation. It comes from acceleration." Looking at the equations for time dilation, time dilation comes from...

I thought of this description recently and I think it's pretty intuitive, but I've gotten some side eye telling it to friends and family (maybe because relativity is screwy, maybe because I'm confused, maybe both?) so I want to get some confirmation that it's reasonable. Here goes: If you're in...

I think, since the train is decelerate the kid will fall off at free falling. the time for that is: y=0.5*9.8*t2 ⇒ t=√(2*y/g)=√(2*3/9.8)=0.8sec. Now i think i need to find what is the distance the train is doing in this time, but i can't figure this out.

I'm a physics undergraduate student. Im gonna try to tell you the short version of my story. I used to be in a different science field, but always wanted to pursue physics. The reason I didn't do so at the start is because my parents were opposed to the idea (i was 17 and didn't argue much at...

The question is as seen below: My attempt (note that my questions are in bold below) is below. Please note that I am self-studying AM: (a) By the independence of any interval ##dt## of time and time symmetry, we expect these two answers are the same (Is there any way to make this rigorous?)...

(Not sure about the prefix. Choose intermediate to be sure.) This article Physicists Recreate Classic 'Double-Slit' Experiment Using Time Instead of Space has it's basis in this paper: Double-slit time diffraction at optical frequencies It certainly sounds intriguing but is there actually...

I'm looking at Dirac's "Lectures on Quantum Field Theory" and I have a question about the basic mathematics of something that's part of ordinary quantum mechanics. On page 3, he says, The two pictures are connected in this way: any Schrodinger dynamical variable is connected with the...

Is it generally the case even with light like paths that ##\dot t>0##?

This was a practice question, so it had the answer with it, which is 31 minutes. However, I'm confused as to why Lisa experiences T0. It isn't exactly an event happening in Lisa's rocket, but rather her just moving through space. From her perspective, it should look like Earth is moving at the...

So at first I thought that the time would be 10 years, and that I’d have to consider the outbound motion as v = .87c and inbound motion as v = -.87c but I’m struggling with addition of the velocities and whether or not this is even the right approach?

The non-moving clock will see the other one move upwards and land as predicted by Newton's laws, so using the equation ##z=v_0t-\frac{1}{2}gt^2##, and assuming the moving clock starts at ##t=0##, it will land at ##t=\frac{2v_0}{g}##. Now, using SR only, and the Minkowski metric (with signature...

Out of curiosity, how fast are the hands of the pros? I have timed an exchange between BJ/ALW and JD/JI that occurred at the Baird PPA in September 2022. The ball made the (about) 14 foot trip 11 times over 4.0 seconds, for an average trip time of 363mS (milliseconds). (Average speed of 26.3...

When we observe distant time dilation effects, usually indicated by redshift, there are three possible explanations: 1) The speed of light, is slower there and then; 2) Space, is contracted for light there and then; 3) The frequency, of specific light is slower there and then. However, it is...