All Questions
33
questions
5
votes
3
answers
643
views
Special relativity and accelerating twins
Imagine two twins synchronise their clocks and then twin A quickly accelerates to velocity v. After a time T twin B quickly accelerates to 2v and catches up with twin A. Which one will be younger? How ...
- 81
0
votes
1
answer
44
views
Relativity - how do you calculate the duration of this trip from various reference frames?
Let's have following scenario:
A spaceship departs from the Earth and constantly accelerates in a straight line for 60 000 000 seconds at 1g (10 m/s^2), then immediately starts decelerating at 1g for ...
- 11
-1
votes
2
answers
79
views
Does the length of an object change after acceleration in Special Relativity? [duplicate]
In special relativity, an object (a box, perhaps) travelling at 0.5c relative to us, if it thinks it's 1lightsecond long in its own reference frame, will look 0.866 lightseconds long to us.
My ...
- 160
0
votes
1
answer
115
views
Observed time period in distant clock when moving towards it
Imagine, 2 persons ('A' & 'B') are 6 light years apart in space, stationary to each other and with no gravitation acting on anybody. Suppose 'B' starts his clock which also shows years, months and ...
- 15
0
votes
0
answers
67
views
Proper time of an accelerating particle
I am supposed to find the proper time of a particle whose worldline is given by:
$$\begin{align}
x(t) &= \frac{3}{2} a t^2\\
y(t) &= 2 a t^2\\
z(t) &= 0
\end{align}$$
where $a = const$ and ...
- 131
0
votes
0
answers
26
views
Question on Example 5.9 of Prof. Hartle Gravity textbook
I'm reading the Gravity Hartle book (ed.2003) and I'm having trouble with the question in the last part of Example 5.9 - Frequency Measured by an Accelerating Observer. More specifically the problem ...
- 1
1
vote
4
answers
165
views
Is constant acceleration the same relative to other objects at all velocities?
If you are accelerating at a constant rate of 10 $m/s^2$, will you see things around you move at 10 $m/s$ faster every second, even when approaching the speed of light?
a) If not: How do you calculate ...
- 171
0
votes
0
answers
61
views
Is this the right way to think about accelerated observers?
$c=1$
I'm trying to think of a way to understand the change of coordinates from an observer at rest to an accelerated one. Clearly, a single Lorentz transformation with $v=v(t)$ is not the right way ...
- 391
0
votes
0
answers
29
views
How would we perceive a pulse of light if we accelerated constantly in the same direction? [duplicate]
I'm watching this video (the link starts at the relevant timestamp) and am confused about one thing. Let's say I'm going at a constant speed of $0.99c$ in $+x$ direction (w.r.t Earth), and a pulse of ...
- 1,240
0
votes
0
answers
27
views
Is it correct to say that acceleration slows the frequency of an oscillator?
My question is based on differential aging or differential timekeeping due to, 1) increased speed, and 2) proximity to center of gravitational field. As far as I know, both involve acceleration, and ...
- 1
2
votes
1
answer
122
views
Can you experience length contraction in an accelerating reference frame?
Imagine I am floating in space some large distance X above a neutron star or high mass object and I am using rocket boosters to stay stationary relative to the object. Assume no other forces acting on ...
- 21
-2
votes
1
answer
168
views
In the twin paradox without acceleration, how is the symmetry broken? [closed]
In the twin paradox without acceleration, where $A$ is "stationary", and $B$ makes a journey and then turns back, we can just as easily suppose $B$ is stationary and $A$ is the one who makes ...
1
vote
4
answers
308
views
Some confusing points about Bell's spaceship paradox from a video
I was looking this video about Bell's Spaceship Paradox on Youtube titled This Paradox Took 17 Years To Solve. It's Still Debated. Please note that the video starts at the segment I have a question ...
- 717
0
votes
2
answers
196
views
Layman question about relativistic motion
I hope I can convey my question in a reasonable way:
I know that if Alice is moving towards Bob at $0.75\,c$ and Bob does the same towards Alice, then to calculate how each one of them measures their ...
- 1
-1
votes
5
answers
138
views
What is preventing this statement to be true: the twin brother who accelerated away is really decelerating
To summarize the twin paradox: the brother who was in the rocket and flew away is the one having a slower time, because he "accelerated", decelerated and then accelerated again and came back ...
- 332