349 views

### Can speed of light be $c$ in air or other medium?

I know that the speed of light in a vacuum is $c\sim 3\ 10^8\ \mathrm{m/s}$, but I also know that speed of light in a medium (e.g., air) is less than that in vacuum. Special relativity says that ...
194 views

### A rope between Earth and Moon - Length and Speed of Light [duplicate]

An earlier question was asked on what would happen if a rope was attached between Moon and Earth, but the question was more about the impacts in terms of geology. We keep the same experiment setup : ...
1k views

### Is thermal conductivity correlated with speed of sound in metals?

Right off the bat I should say: thermal conductivity and electrical conductivity are definitely correlated in metals. image source: https://www.doitpoms.ac.uk/tlplib/thermal_electrical/printall.php ...
94 views

### Rope with no slack tied around the world [duplicate]

Imagine a "rope" (for want of a better word) is wrapped all the way around the Earth, to the point that you can hold both ends. There is no slack on the rope, i.e. it doesn't stretch. It also isn't ...
244 views

### Hypothetically what would happen in this situation? [duplicate]

Would the speed of 'push' be equal to the speed of sound?
111 views

### What prevents an orbiting object from getting a speed which is greater than $c$? [duplicate]

Consider an object orbiting around a point with radius $r$ and angular velocity $\omega$. Here its linear velocity is $v=\omega r$. If we choose a large enough $r$ and reasonable $\omega$, $v$ might ...
1k views

### Spinning theoretical object moving faster than the speed of light [duplicate]

Let's say you have the Earth, or any celestial body, spinning as it is. What if you build a tower from the surface, and extended it out into space. If it was built far enough, could the furthest end ...
33 views

### What will happen if a stick and a beam of light is to race [duplicate]

I don't know whether the question is asked before on not on this website as I can't found it anywhere so I have to ask. What will happen if a place a long stick with a length of a light year. Rather ...
53 views

### Superluminal Thought Experiment [duplicate]

If I had a weightless, indestructible rod that was 1,145,915,590 meters long and I moved it 15° would the end of the rod go faster than the speed of light? (Assuming it's path is unobstructed.) ...
31 views

### do information travels faster than light? [duplicate]

Suppose a long rod of length 6 lakh kms is subjected to movement at one end,does it move immediately or not at another end?
172 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 really) one ...
141 views

### Check where am I wrong. Here is how information can be sent faster than light [duplicate]

If I have a very long rigid rod which is of rectangular cross section and small mass. Let it's length be 1 light year and total mass be 1 kg now at one end if I rotate that rod, since the rod is rigid ...
190 views

### Speed bigger than light? [duplicate]

We know, according relativity theory, no information or matter can travel with velocity bigger than light. However, consider the following situation: a completely empty water hose is hypothetically ...
59 views

### Moving a 2x2 the length of the solar system [duplicate]

If we were able to push a 2x2 piece of wood that is the length of our solar system, how would it behave? My colleague says since its all part of the same molecular structure, the whole piece of wood ...
33 views

### How quickly is momentum transferred through an object? [duplicate]

If there was a pole, that was a light year long, out in space. (Away from all physical interference.) If we pushed one end of it, would the other end move instantly? And does it's speed depend on ...

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