Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the conscious experience. Time is often referred to as a fourth dimension, along with three spatial dimensions.Time has long been an important subject of study in religion, philosophy, and science, but defining it in a manner applicable to all fields without circularity has consistently eluded scholars.
Nevertheless, diverse fields such as business, industry, sports, the sciences, and the performing arts all incorporate some notion of time into their respective measuring systems.Time in physics is operationally defined as "what a clock reads".The physical nature of time is addressed by general relativity with respect to events in space-time. Examples of events are the collision of two particles, the explosion of a supernova, or the arrival of a rocket ship. Every event can be assigned four numbers representing its time and position (the event's coordinates). However, the numerical values are different for different observers. In general relativity, the question of what time it is now only has meaning relative to a particular observer. Distance and time are intimately related and the time required for light to travel a specific distance is the same for all observers, as first publicly demonstrated by Michelson and Morley. General relativity does not address the nature of time for extremely small intervals where quantum mechanics holds. At this time, there is no generally accepted theory of quantum general relativity. Time is one of the seven fundamental physical quantities in both the International System of Units (SI) and International System of Quantities. The SI base unit of time is the second. Time is used to define other quantities – such as velocity – so defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. To describe observations of an event, a location (position in space) and time are typically noted.
The operational definition of time does not address what the fundamental nature of it is. It does not address why events can happen forward and backward in space, whereas events only happen in the forward progress of time. Investigations into the relationship between space and time led physicists to define the spacetime continuum. General relativity is the primary framework for understanding how spacetime works. Through advances in both theoretical and experimental investigations of space-time, it has been shown that time can be distorted and dilated, particularly at the edges of black holes.
Temporal measurement has occupied scientists and technologists, and was a prime motivation in navigation and astronomy. Periodic events and periodic motion have long served as standards for units of time. Examples include the apparent motion of the sun across the sky, the phases of the moon, the swing of a pendulum, and the beat of a heart. Currently, the international unit of time, the second, is defined by measuring the electronic transition frequency of caesium atoms (see below). Time is also of significant social importance, having economic value ("time is money") as well as personal value, due to an awareness of the limited time in each day and in human life spans.
There are many systems for determining what time it is, including the Global Positioning System, other satellite systems, Coordinated Universal Time and mean solar time. In general, the numbers obtained from different time systems differ from one another.
Equations:
Question:
Using the equation for t' I got the answer -0.00000499756s (Wrong anyway)
As we know the values:
v = 0.67c m/s
x = 3900 m
t = 0.000005 s
Also how can time be negative? Does this mean that event 2 happened before the first event when t = 0?
Hello, I have the force defined as a function of time, where F=A-Bt and A=100N, B=100Ns-1. I have to determine, how long it will take for object to stop, if t0=0s and v0=0,2ms-1 and mass of the object is m=10kg. Can somebody please help me with this, because I'm having hard time with this task.
Tonight I'm taking my wife and parents to Brian Cox's World Tour "ADVENTURES IN SPACE & TIME" with sidekick Robin Ince. All his European stops sold out and so far all of his US stops have been close to selling out. I've been impressed because he's not quite the household name Neil deGrasse Tyson...
Note: Maths has always been kinda a weak point for me in school. Anyway.
From hereon I'm going to talk about this in the context of a train for simplicity, even though this is actually needed for an entirely different context - but I don't think this is relevant for the problem.
In terms of my...
Hello,
I've got this question:
A 16 MB file is compressed using a compression ratio of 4. The resulting compressed file is transmitted over a wireless connection that offers a maximum data rate of 1.2 Gbps. If a throughput of 60% can be achieved, and assuming there are no other transmissions...
Hello people,
I have a question regarding the time calculation.
could you please let me know if there are any equations with which I can find the time to generate steam in the header for certain pressure level.
lets say I am supplying fuel and mass flow of water to the boiler at certain...
Hi, I have some crucial questions belong to statistics:
First, How can we derive the variance function with respect to mean for a given data?
Secondly, I would like to ask: what method should we employ if the variance in time series behaves like a high order (such as ##𝑎𝑢_𝑡^5+𝑏𝑢_𝑡^4+𝑐𝑢_𝑡^3##...
Is it possible that time is just another coordinate axis? That it can be moved freely into backwards and forwards at any speed. And for some reason we as humans can only see it moving forward? and communicate at a definite speed in time.
Maybe everything is already calculated and solved, and...
It is obvious that there is a one-to-one relationship between real numbers (defined to include infinity) and their multiplicative inverses (assuming we map the inverse of zero to infinity and vice versa). Thus, one should be able to replace the distance between two points in space with it's...
I just watched a youtube video saying that somewhere in a black hole, time is bidirectional (can go to the future and can go to the passed), but space is one-directional.
Any introduction material on this subject?
Thanks in advance!
All I've done so far is think about F_net. Since F=ma, and a is a vector, I was thinking that I should find the x and y components of a and then try to calculate F_net that way, but I'm confused as to where I should use x(t) and y(t). Or instead, thinking about it as the change in momentum over...
Since the metric is euclidean in coordinates ##(ict,x)## it can be drawn in a plane, but if the metric is ##diag(1,-1)##, can both axis still be drawn in a plane ?
here I am trying to find ##\frac{d}{dt}dx## where ##x(t)## is the position vector
Now ##\frac{d}{dt}(v_x(x,y,z,t)dt)=\frac{dv_x}{dt}dt=\frac{\partial v_x}{\partial t}dt+\frac{\partial v_x}{\partial x}dx+\frac{\partial v_x}{\partial y}dy+\frac{\partial v_x}{\partial z}dz##
Now dividing by ##dx##...
I have been reading a book on classical theoretical physics and it claims:
--------------
If a Lagrange function depends on a continuous parameter ##\lambda##, then also the generalized momentum ##p_i = \frac{\partial L}{\partial\dot{q}_i}## depends on ##\lambda##, also the velocity...
I came up with this formula.
A takes 20 days to have 80% completion. Simple algebra gets that A takes 25 days to complete finish by themselves. Now I'm trying to come up with a formula.
##1/.8(1/25) = 1/20## with 80% completion. Now I'm working with the remaining 20%. ## 1/.2(1/25+1/b)##...
The Singapore Flyer is a very tall Ferris wheel.It is 315 meters tall and has a diameter of 150 meters. Each revolution takes about 30 minutes. If you were allowed to ride for 3 hours, how far would you travel? How much of a mile or how many miles would you travel?
For Initial Value problems I want to implement an ODE solver for implicit Euler method with adaptive time step and use step doubling to estimate error. I have found some reading stuff about adaptive time step and error estimation using step doubling but those are mostly related to RK methods. I...
I accept that time can pass at different rates depending on if the applied motion or gravity (both a parameter in some formula) and as a result time passes at a different rate. However, this seems to imply that we have some control over how slow time may pass. So, if that is just a fact of the...
I would like to ask a question on whether there is a proportionality between volume of a balloon, and the time it takes to deflate.
I have conducted several balloon hovercraft experiments. I need to find the relationship between the amount of air pumped into the balloon and how long the...
I'll confess, I joined this forum solely to understand the reasoning behind the concept of time dilation, and to see if it is correct or not. If anyone could help me understand it better, and converse with me, I'd greatly appreciate it.
Is time dependent on the motion of everything in the universe? If all motion was played in reverse, so particles gain kinetic energy from sound and heat energy as they move the opposite direction, and light retreats into the sun, would time technically now be flowing backwards? If all matter (so...
Why do we use the equation ##\frac {1}{2}mv^2 = \frac {GmM}{r}## to derive potential velocity, and then put that in the Lorentz factor in order to derive gravitational time dilation? Shouldn't we be using the relativistic definition of kinetic energy -> ##mc^2(\gamma - 1)## to derive the...
Quantum fields have wave functions that determine a particle position in space. It solves non-locality, double-slit paradox, tunnel effect, etc. What if the wave function is also in time? Won't it solve the breaking of causality at quantum level? (Delayed Choice/Quantum Eraser/Time)
Not much...
Is my solution reasonable?
What I got from my first attempt is that the time constant won't change. WHY? Because when we double the number of loops (N) we're going to have new values for both the self inductance and the resistance of the solenoid and so the ratio (L/R) stays the same. Here is a...
Is there some sort of special format of proposal they must put together?
Do they need institutional support (from their university, dept. chair, company, etc)?
Are there costs involved?
Does it depend on the facility?
Does anyone know where I can get this sort of information?
Thanks in...
I am currently a community college student majoring in Computer Science, and I was placed into Calculus 1. I had to withdraw from this course for two semesters now. My professor advised me that I have "Algebra Issues".
With my weaker foundation of Algebra, I plan to take the College Algebra...
I am able to solve the problem however if x was position and t was time how is this problem interpreted?
I know, for example that ##\frac{dx}{dt}## tells us how the position of something changes as time changes (or instantaneous change) and an integral gives a net change so to speak.
.
The above are some of the typical problems related to Poisson Process. I need to understand the difference between time, inter-arrival time, and arrival time in this regard.
Say, we start our counting from 9:00 AM and count up to 10:00 AM.
Image-1: arrival process.
1. 1st call comes at...
Hello,
Let's imagine we have an infinite plane (or large enough compared to the region of interest and measurements) pierced in normal direction by magnetic field B which is uniformly distributed but time varying. For the sake of simplicity we'll presume the magnetic induction is linearly (and...
I'm a physics student and science fiction writer, and I've never been to this section of PF before! But I have an idea I think is cool for a novel or short story and I'd like some input on the physics involved. As I'm not overly worried about this idea being stolen I'm going to provide a short...
Problem Statement
I was watching a YouTube video regarding the calculation of expected return time of a Markov Chain.
I haven't understood the calculation of ##m_{12}##.
How could he write ##m_{12}=1+p_{11}m_{12}##? I have given a screenshot of the video.
Hello!
It says that the Time Constant of an RC circuit is equal to 100 ms. What is the energy that remains in the circuit after 300 ms? "Nothing mentioned about whether it is in falling or rising edge".
The formulas that I have been using are :
W = 0,5 (C* V^2)
V = V0 ( e^-t/rc )
since I don't...
So I had a topic which I would like to fact check from an informed scientific source.
Basically there is an argument about whether or not an object that naturally exists in a fourth dimensional space, would by default have more than countably infinite times the energy of a 3 dimensional Object...
Hi,
I have provided a procedure for broadcast for BBT at the following link:
https://cs.stackexchange.com/questions/106631/all-to-all-broadcast-on-a-balanced-binary-tree
But I am not getting the correct time as asked in the question:
Required Timing equation is: ##(t_s + t_w * m* p/2)logp##...
Hi,
Kindly consider the Question 4.8 on the following link
http://parallelcomp.uw.hu/ch04lev2sec18.html
##t_s## = start up time
##t_w## = per-word transfer time
m = size of message
p = number of processors
The total time for communication for ##logp## steps is:
##T = (t_s + t_w*m) * log_2 p##...
I know that has been discussed elsewhere but never could find for a satisfying answer, so I try this here again.
Let us not take into account that an observer (an astronaut or a clock or just let us take both: an astronaut with a clock) falling into a black hole (BH) will be killed and torn...
Could a particle be sent back in time on it's world line? Time is defined by events, but at absolute zero, there is no movement or vibration of a particle - does not time cease to pass then at absolute zero for the particle? If the particle was somehow brought below absolute zero, could it be...
for part 1: t= d/s = 9000/13 = 692.31s
for part 2: What i am unsure about is wether or not this is after the initial observation or exactly what they are asking honestly. so i found the relative velocity of the bus to the car and vice vera and came up with: t=d/s = 9000/4 = 2250s however i don't...
There are quite some pop-sci books (by Greene, Smolin, Carroll and others) that deal with the "nature of time". Why does time appear to flow? Why is there a special moment, the "now"? Does simultaneity in SR imply a block universe? Why time-symmetric laws but a time-unsymmetric universe? Does...
So I am having some hard time understanding exactly the effect of moving near light-speed on time. Most of the examples mention clocks as a way of measurement but I can understand why would a clock which is a mechanical or electrical device for measuring time would be effected with motion. That...
Since for the two events of Samir starting the stopwatch, and the stopwatch reaching 10.0s, Samir and his stopwatch are stationary from his own frame of reference, I said it was the proper time and that delta t0 = 10s. Then the speed of the moving frame of reference was 0.6c. I thought placing...
Watching Dr. Susskind show how to find the time evolution of the average of an observable K, he writes:
I can not for the life of me figure out he derived it, and he also did something which I found terribly annoying throughout which is set hbar to 1, so after steps you lose where the hbar...
A 2000 kg truck is resting at the top of a parking lot ramp which is at a 15 degree slope. It is then shifted into Neutral and starts moving.
How long does it take the truck to get from A to B in seconds?
There is a 15 degree slope on the ramp.
uk is 0.08
Assume there is no air resistance.
Hey all, it's been awhile since done any calculus or DE's but was trying out some modelling (best price price per item for bulk value deals as a function of time and amount), in the last line i have f(n,t) implicitly.
Any pointers or techniques for solving such things?
In this paper ##J=\frac{\partial f_1(X_1)}{\partial X_1}\frac{\partial f_2(X_2)}{\partial X_2}\frac{\partial f_3(X_3)}{\partial X_3}## where ##f_2(X_2),f_1(X_1),f_3(X_3)## evolves with time.
Now using this ##\dot J=\frac{d}{dt}(\frac{\partial f_1(X_1)}{\partial X_1}\frac{\partial...
Hi,
as Easter is slowly approaching, I came up with an egg cooking thermodynamics problem that I would like to solve. My formulation of the problem including necessary simplifications is as follows:
Let's assume that an egg is a sphere-shaped solid body made of homogenous material (ignoring...
So, I have this idea for the FTL engine for artistic purposes and I wanted to ask if anybody could point out it's flaws. I would greatly appreciate if you were willing to discuss them further. It is just a rough summary, so if you want me to disclose more details, ask away.
The idea is as...