Recent content by bucher

For the steam engine, you need to consider the surroundings as well. Though 10 units of heat is more chaotic than 2, we are only considering the system at this point. Also, it is not just the heat that determines the entropy change but the change in temperatures of the system and surroundings...

Q = mc(delta T) is not the correct equation in this example for the system. It has already been stated that Q must equal W in an isothermal process. Think of it this way, if the system is a piston and the piston is drawn up then the system should cool. To keep the system at a constant...

The detectors on the train will be affected by time delay as well. Everyone/everything on that train will be affected. In order to see the cat, photons will have to bounce off the cat and reach an observer. It takes time for the light to reach that observer. When the cat is struck by...

thanks again, this makes a bit more sense to me.

The two times observed (embankment and train) are different. The cat was struck by lighting at t according to the embankment and it was struck at time t' according to the train. The two times are different when compared. The reason why they are different is because the train was moving relative...

If the cat was struck by lighting at time t according to the embankment, then it would be struck at time t' according to the people in the train. You have to account for relativity due to the train's speed and the distance that the light needs to cover to reach the train's observers.

Thanks, this helps me out a lot.

Though the observers on the train see the lightning as non-simultaneous. They can still calculate to see what the embankment would observe. It's not like they are barred from thinking that someone else could have observed something differently. The book is stating that when an observer sees two...

1. What the book is trying to convey is that, according to the observers on the train, the two lightning strikes happened at different times. The observers could very well think that it was simultaneous to someone else. But to those observers on that train the two events were not simultaneous...

Let me rephrase my example. I'm out in space with an emitter that fires one photon at a time. I get the emitter to point away from me and move downward at a constant speed of 10 m/s. When the emitter is going at this constant speed it fires a single photon. Will the photon have a downward...

For issue #1, placing light detectors at the points of the train where the lightning strikes would show simultaneity (the light would have to travel the same distance towards the moving detector). Simultaneity is relative to the observer. What may happen at the same time for one may happen at...

Yes, though the affects are insignificant with the hose, the affects are still there (small, but there). I didn't know if the trajectory of the laser pointer affected the trajectory of the photon no matter how small.

Thanks. I'm still trying to get the duality of light concept and wasn't sure how a photon would react in these situations.

This isn't homework but I need to ask my question with an example. Say you're out in space and you have a laser pointer. You point the laser pointer straight out in front of you and turn it on. You're able to leave the laser pointer on without holding onto it, so the laser pointer is just...

dv/dt is not a symbol. It is the mathematical formula for the derivative of v with respect to t. This is how one would show any derivative of a dependent variable with respect to an independent variable.