# All Questions

717 views

### Event horizons without singularities

Someone answered this question by saying that black hole entropy conditions and no-hair theorems are asymptotic in nature -- the equations give an ideal solution which is approached quickly but never ...
2k views

### Does wind speed things up or accelerate things?

This question may seem odd, but I can't think of anything better. So I'll go straight to the point. Let's say there's a projectile in air going east, shot at a certain angle, with a certain speed. ...
1k views

### Time Reversal Invariance in Quantum Mechanics

I thought of a thought experiment that had me questioning how time reversal works in quantum mechanics and the implications. The idea is this ... you are going forward in time when you decide to ...
375 views

### Optical Tunneling

Is there light tunneling taking place in optically transparent mediums like glass? wherein light travels a larger path in these mediums without interacting with atoms and without any change in ...
158 views

### Please explain this circular movement problem [closed]

I was working over some problems from my physics textbook, and I came across this one, it involves circular movement: A car with the mass of 1t is moving over a hill with the velocity of 20 m/s. The ...
316 views

### What could I test for in a guillotine? [closed]

I'm doing a school assignment project and I need to investigate something of my choice. I was thinking of doing something about how the height and angle the blade of a guillotine is dropped from ...
189 views

### Does using batteries in a series raise the overall Wh's of the batteries used? Why/Why Not?

If one has 2 batteries of 6 Volts each with 500 mAh each, then separately the batteries should provide 6 Volts * 500 mAh = 3 Wh each or 6 Wh total. However would it be the case that if someone where ...
207 views

### An introductory resource for learning AdS space

Can someone please point me to introductory resources about the geometry of Anti DeSitter Space ? What are some examples of other spaces used in theoretical physics ?.I'm learning Differential ...
424 views

### Graphene Moebius Strip

I'm refering to the Paper: PHYSICAL REVIEW B 80, 195310 (2009) "Möbius graphene strip as a topological insulator" Z. L. Guo, Z. R. Gong, H. Dong, and C. P. Sun. The paper is also available as a ...
747 views

### Is this a quaternion Lorentz Boost?

The quaternion Lorentz boost $v'=hvh^*+ 1/2( (hhv)^*-(h^*h^*v)^*)$ where $h$ is $(\cosh(x),\sinh(x),0,0)$ was derived by substituting the hyperbolic sine and cosine for the sine and cosine in the ...