Time Definition and 1000 Threads

As far as i know, current special relativity allows for time traveling but only in the future. In sort what we have to do to travel to the future, according to special relativity, is to make a spaceship that can achieve speed comparable to the speed of light. Then while we are traveling with...

Hello, Dear Readers, as mentioned in the caption and Summary, i'am dearly interested in the perception of time due to relativity. I thought About this for quite some time.What happens to the perception of time to the conciousness, I mean our weight is not the same, and our energy consumption...

I've got a good conceptual understanding of relativity (not maths based,) but the one thing which I can't quite get my head around is being able to influcence my casual past. I can picture being able to leave my light cone with faster than light travel, but not to the point where I could go...

Good morning I'm a total beginner in physics, but I recently started to read books and watch videos about cool physics stuff, like relativity. I heard that the closer to the speed of light you travel, the "slower" time passes for you. I'm talking about the fact that clocks in GPS satellites...

My homework assignment asks "Record the drop time to the nearest 0.01 or 0.001 seconds". Is there a stopwatch online I can use? Thanks. MaryM

Hi everyone! I am studying spectral methods to solve PDEs having in mind to solve a heat equation in 2D, but now i am struggling with the time evolution with boundary conditions even in 1D. For example, $$ u_t=k u_{xx}, $$ $$ u(t,-1)=\alpha, $$ $$ u(t,1)=\beta, $$ $$ u(0,x)=f(x), $$ $$...

Imagine this question in 2 dimensions, time (t) and distance (x), that is (t,x). Alice (A) is at the origin, x=0. Bob (B) begins at x=c. Thus we have A(0,0) and B(0,c). Both Alice and Bob send a light signal towards the other but let's say the signal changes colour every second by the colours of...

Presume we look at a two-dimensional view of space time, with no local masses, and we draw a grid of equidistance spaced lines. The intent is to look at space but not time. As we begin, we look in all directions and the grid lines are evenly spaced. Begin adding mass to the center of the grid...

If we were to sit inside a black hole, of infinite mass what would we see ? Would you see time move around you? If I shine beam of light, after 1 year , relative to me the beam of light 1 year away, however if I manage to get in front of that beam, I will be at the same point in time. Would...

Hey! 😊 We have the following tasks with the respective times of execution: \begin{equation*}\begin{matrix}T_1/5 & T_2/4 & T_3/8 & T_4/3 & T_5/4 & T_6/6 & T_7/8 & T_8/3 & T_9/5 & T_{10}/3\end{matrix}\end{equation*} The tasks $T_3,T_4$ have as prerequisite the task $T_2$, the tasks $T_5, T_6...

Could I please ask for help on the last part of this question: So, part b, I get the right time but not the right distance. Book answers are: distance = 1/6 and time = a/V. Here's my (faulty?) reasoning (LaTeX isn't working for me): The boat is steered due east and so would have a velocity...

So I understand that time is now part of the four vector, and so dividing delta X by delta t (time according to me), would produce just c as the first dimension of the vector, which gives us no intuition as to how fast time is moving for the observer, so is not useful. I understand why we...

Can anyone please help me see if my reasoning is correct regarding the following question? I'll just solve for the case where the dinghy tracks so as to just 'touch' the exclusion zone on the 'high' side So, in the diagram below: The dinghy tracks along the red path, inclined at x degrees...

Okay, so what I attempted for a) is to use Bernoulli's. The velocity of the fluid in the chamber should be equal to the velocity of the piston, which in comparison to the barrel should be negligible. Hence I get \frac{p_1}{\rho g} = \frac{1}{2} \frac{v_2^2}{2} + \frac{p_2}{\rho g} so \Delta...

I was absent for a while due to personal constraints but I did keep myself busy with the Time dilation equation some member sent me a while back. I decided to set a time limit for myself to learn and understand time Dilation and length contraction, which must be before December 2020, or I will...

I am more confused by the theory of relativity as I start thinking about it. I have a question and it might sound silly but please, correct me if I am wrong. Suppose, A and B are twins where A is at the Earth, and B is moving on a spacecraft at a speed near to the speed of light. In this...

I'm studying Ergodic Theory and I think I "got" the concept, but I need an example to verify it... Let's take the simplest possible 2D classical harmonic oscillator whose kinetic energy is $$T=\frac{\dot x^2}{2}+\frac{\dot y^2}{2}$$ and potential energy is $$U=\frac{ x^2}{2}+\frac{y^2}{2}$$...

Is it theoretically possible that the whole universe is decelerating in time? My question originates from the discovery, that objects further away accelerates away faster. Is that acceleration measured from us or from the center of the big bang?

I first calculated initial velocity: √7.09^2+1.07^2=7.17028 acceleration=√7.22^2+2.47^2= 7.63 then i substituted all values into this equation: final velocity=initial velocity + acceleration x time so, final velocity=82.0285 so the magnitude= final velocity-initial velocity= 74.858271 is...

This is the graph I was given and the answer options. Since the graph is a straight line moving towards the positive direction I thought that meant it was traveling at a constant speed moving in the positive direction. That ended up being the wrong answer. Can anyone offer insight, I missed each...

My answers: a) At points d the instantaneous velocity should be greatest since slope of c-d is greatest I think b) At point e and g instantaneous velocity is 0 c) at points b, c, and f instantaneous velocity is negative. Could you please verify my answers?

Hello, I wrote a program that adds force to a car like so: Engine Force = Power / Velocity Drag Force = -Velocity² Net Force = Engine Force - Drag Force = Power / Velocity - Velocity² I'd like to determine power based on how fast I want a car of a given mass to reach a given speed, for...

I've tried to solve the following circuit using mesh equation, but the solution seems to differ from my attempted answer. Mesh circuit as follows: My mesh equation is: -10+3(i1)+2s(i1-i2)=0 (for the mesh on the left) and -10+12(i2)+6s(i2)+2s(i2-i1)=0 (right mesh) However the answer seems to...

Thank you in advance for your replies. While reading about special relativity I started thinking about how time dilation might affect temperature. Since temperature is really the jiggling motion of molecules, does time dilation affect temperature by slowing down the jiggling motion? Or...

I am looking at the module HLK-5M05, which is a ##5\ V, \ 5\ W## AC-DC power supply module. The advantage of this module is that, it does the stepping down and rectification within itself, and is a switching source, so fluctuations in the voltage grid won't affect the output (at least that's...

In this example, We need to covert e2 & e5 to a form with imaginary number . we will obtain e2=j10 & e5=20 Can anyone explain how we got this?

The first part I have calculated is as follows:: Length of A seen by S =30m Length of B seen by S=40m In S frame, Time for front of A and B to come in same line 0.8ct=40+0.6ct...t=200/c From the above position time for back end of A and front of B to come in same line 0.8ct=30+0.6ct...t=150...

I get the same values for both observers, which is not nice I think.

While attempting this question , velocity of ##B## wrt ##A## ,##u'_x=\frac{u_x-v}{1-u_xv/c^2}## where ##u_x=-0.6c,v=0.8c## comes out to be ##-0.945c## (approaching).. The distance between ##A## and ##B## seen by ##A## at ## t=0## is ##d=\sqrt(1-.8^2)4.2×10^8## comes out to be ##252*10^6m##...

I thought I had a decent basic understanding of this stuff, but it turns out I've got quite a lot of gaps. I drew 3 frames, S, S' and S", where S' and S" move at ##v_1## and ##v_2## w.r.t. S in the ##x## direction, and two different paths to a particular event P: Now the proper time between...

I use UVC to sanitize. However, since I sometimes use HID lights, when it comes time to flip over or change the angle of objects and the light is deactivated, there is a 10-15 min cooldown period before the light will reignite. I have been thinking of using a rotating platform that would have...

Mod note: Initially posted in a non-HW forum section, so missing the template Summary:: Hi, I am trying to find CPU utilization What is the CPU utilization if there are 5 processes running at the same time, and on average the CPU spends 30% of its time waiting on I/O completion? The formula...

I’ve tagged this question as “Basic”, although I’m not sure if it can be answered at that level. A friend pointed me to this article: https://www.msn.com/en-ph/news/opinion/what-einstein-may-have-gotten-wrong/ar-BB12w95x Here’s a quote: In other words, the world is indeterministic; the future...

Happy Birthday Evo 🥰🥰🥰

There are many examples where physics explains why sensations of the same phenomena (e.g. lightning) affect senses at different times ( flash of thunder vs sound of thunder). What are notable examples where it's mainly the speed at which the brain processes sensations that explains a time...

For case B- Conditions: 1. The observer was observing since the time they were in contact. 2. There are only 2 directions for motion: back and forward. 3. Relative velocity is not equal to zero. 4. Bodies are moving away from each other Time difference = t Relative velocity = v Distance between...

Time as we perceive is not a universal constant. It depends on the speed of the bodies and the distance between them.

I’m trying to come up with a term to describe how time moves slower or faster in different places of a galaxy. I’m trying to explain how in Star Wars, things seem to move differently for different characters in separate locations. I’m trying to argue that Han limping to Bespin took “longer” than...

probably a daft question asked before, but. if space is expanding at an accelerating rate would that mean time is accelerating too?. after all Einstein* claims and the maths seems to say that space and time are the same thing, ie space-time. so if space is expanding faster and faster shouldn't...

Here is my not particularly well thought out Earth Day Proposal for your collective consideration. The building of palm oil plantations is often cited as a driver of tropical rainforest deforestration (which is thought to contribute to climate change in a variety of ways (I'm not providing...

Hi, I am trying to understand the running time of FF both the original and improved version. For the original version book says: What I understand from this that before placing the items, FF traverses all the bins from beginning to end i.e. n bins. Now each bin can have n items, because of...

Hi guys, i hope i find the right Sub-Forum. Can you please tell me if i calculated it right. A car speed's up with 5 m/s² to a speed limit of 50Km/h. After it arrived the speedlimit it drives for 30s with the speed of 50km/h. After that it break with a negative acceleration 3.0m/s² to stop...

Could I please ask for help with the following question (the second part): A cruiser sailing due north at 24 km/h sights a destroyer 48 km due east sailiing at 56 km/h on a course (360-a) degress where cos(a)=11/14. Show that the destroyer's course realtive to the cruiser is on a bearing of...

I've been trying to understand gravitational time dilation by considering a light-clock of length ##l## undergoing an equivalent acceleration ##a## from rest along the direction of the bouncing light pulse. I find that the time ##t## that the light pulse takes to travel to the forward receding...

I try to justify time-reversal symmetry in a very simple classical problem; Free Fall. The position, ##x##, and the velocity, ##v## are obtained versus time from the equation ##-g=\ddot x##. So, if we consider the primary conditions as ##t_0,x_0,v_0## it is clear that...

It is fairly trivial to do this with a circular orbit: $$(x,y) = (cos(\omega t),sin(\omega t))$$ where t is time, and $$\omega = \sqrt{GM/r^3}$$ How this parametric equation look for an elliptical orbit?

It shows theory of time machine proved, what's the exact point that stopping our scientists to create time machine in reality?

Hello. I am a filmmaker writing a screenplay and I am in need of technical support to validate a method being used in the film. I am going to post this in the Earth Science forum but I'll copy it here, in case anyone reading this might know. Thank you all! "I am wondering if shadows cast...