Tagged Questions
-1
votes
2answers
75 views
If airplanes' highest speed depends directly on the air it is moving through and not the ground,
If airplanes' highest speed depends directly on the air it is moving through and not the ground, does it mean we can build a time machine if only the air moves near the speed of light?
1
vote
1answer
156 views
Connecting 4-velocity to equation for adding velocities
Is there a way to connect 4-velocity to equations for adding speeds? I know 4-velocity $U^\mu$ is derived like this:
\begin{equation}
\begin{split}
P^\mu &= m U^\mu \Longrightarrow
U^\mu = ...
0
votes
0answers
187 views
Is there an easy derivation of relativistic velocities addition and relativistic doppler shift?
Is there an easy derivation of relativistic velocities addition and relativistic doppler shift?
I'm looking for some easy derivation of the above. Like this ...
2
votes
0answers
44 views
Reaching the speed of light, rockets [duplicate]
Possible Duplicate:
Double light speed
Someting almost faster than light traveling on something else almost faster than light
Well I've been wondering quite a long time about this ...
3
votes
2answers
880 views
How to deduce the theorem of addition of velocities?
Lorentz contraction and time dilatation can be deduced without Lorentz transformation. Can you deduce also the theorem of addition of velocities
$$w~=~\dfrac{u+v}{1+uv/c^2}$$
without Lorentz ...
2
votes
1answer
165 views
Motion is relative, right? And most pop sci relativity explanations are somewhat incorrect?
On page 20 of A Brief History of Time:
. . . all observers should measure the same speed of light, no matter
how fast they are moving.
But in an observer's frame of reference, they're actually ...
1
vote
1answer
156 views
Measuring a Rod in Motion with two Synchronized Clocks
An explanation of special relativity I'm struggling with, goes like this:
A rod traveling by a "stationary" observer has its length measured by use of two stationary synchronized clocks (synchronized ...
2
votes
0answers
155 views
If you make a steel rod from here to Alpha Centauri and move it, will the movement appear there instantly? [duplicate]
Possible Duplicate:
Is it possible for information to be transmitted faster than light?
imagine this theoretical situation:
You have make an extremely long piece of steel (or anything ...
2
votes
1answer
226 views
whats the rate of energy increase required for constant acceleration between 0.0c and 0.99c?
I was wondering how much energy would be required to accelerate 1000kg to 0.99c at 1G.
What I don't understand is what the rate of increase of energy is required as velocity increases. I was looking ...
6
votes
4answers
756 views
Double light speed
Let's say we have 2 participles facing each other and traveling at speed of light
Let's say I'm sitting on #1 participle so in my point of view #2 participle's speed is c+c=2c, double light speed? ...
2
votes
2answers
1k views
Mass of particle near light speed in a medium
I am trying to get a common understanding from these two previous questions:
Why does the mass of an object increase when its speed approaches that of light?
What happens if light/particles exceeded ...
7
votes
9answers
6k views
Why does the mass of an object increase when its speed approaches that of light?
I'm reading Nano: The Essentials by T. Pradeep and I came upon this statement in the section explaining the basics of scanning electron microscopy.
However, the equation breaks down when the ...
