# Tag Info

Accepted

### How could any frame of reference be inertial?

In newtonian mechanics, inertial frames are an equivalence class. They can be defined as frames where Newton's laws are valid. If you can find one inertial frame, then you automatically get an ...
1 vote

### How to represent a pair of inertial frames in relativity?

In Special Relativity we couldn't say in general that the axes of two inertial frames $\:\rm S\:$ and $\:\rm S'\:$ in relative translational motion (boost) are parallel, see Figure-02, except of ...
Accepted

### Dependence (or lack thereof) of forces on frames of reference

When you say "blocks A and B move with a relative acceleration of -3 m/s2" you are considering the motion of one block in the reference frame attached to the other block (block C). But the ...
1 vote
Accepted

### Galilean Transformations Derivation

Let's analyze the spacetime coordinate from the Greek perspective. The Greek will see that the Roman will approach him/her an meet at origin coordinate. Then the Greek perform some measurement at ...

### Recordings of journey traveling near speed of light

Each recorder shares proper time with its corresponding clock, so both sets record and show the same amount of time during playback. The clocks themselves though, after luminal travel, would show ...

### Simple resolution to the twin paradox?

Ronald Hatch proved to us (and it is re-proven every single day with GPS satellites) that the twin paradox simply does not exist. And it does not have anything to do with reversing course or an ...
Accepted

### Riemann curvature tensor in an inertial frame

The fact that a function's first derivative vanishes at a point does not mean that its second derivative vanishes at that point. Note that for $f(x)=x^2$, $f'(0)=0$ but $f''(0)=2$.

### Simple resolution to the twin paradox?

From Alice's perspective, Bob accelerated, travelled far away and then returned. From Bob's perspective, it is Alice that accelerated, travelled far away then returned. No. For both Alice and Bob, it ...

### Simple resolution to the twin paradox?

I'm sorry, Jacques, but as you suspected your explanation is incorrect. The twin paradox seems paradoxical because time dilation is entirely symmetrical, so both Bob and Alice might be expected to be ...
1 vote
Accepted

### Are Newton's laws just definitions?

Your statements starting with "in an inertial reference frame" are indeed trivially true, because of the definition of the inertial frame: inertial frame is a frame where the first and the ...
1 vote

### Simple resolution to the twin paradox?

The calculation you performed clearly shows that distance depends on the observer. This does not resolve the twin paradox since if Alice does the math instead of Bob's perspective then you would get ...

### Invariance of spacetime interval by Schutz

I would suggest you read Landau & Lifshitz argument for invariance of $ds^2$, particularly the Wikipedia link because it states clearly the theorem which is being proved, and it fills in a few ...