The context is the so called warp drive.
In pop-sci articles I've seen the claim that the speed of light limit only applies to objects in space but not the space-time itself, thus claiming that the expansion and contraction of space by a warp drive has no speed limit.
On the other side, I've...
Recently I've stumbled across a preprint in which the author describes a photon is a wave packet and even suggests a transverse extent.
I find it strange, as my understanding so far has been that a photon (and the EM field as such) is a construct used to model certain observed interactions...
I am looking at the field lines or better equipotential lines of a charge. For a charge at rest they are circles. For a charge in motion they are ellipses aligned with the direction of motion (length contraction). The maximum will be measured when the sensors are closest to the circle or aligned...
Thank a lot for the link.
I am looking at the case of the charge passing a row of sensors (y-axis):
z = 0
x - vt = 0
This means:
Ez = 0
Ex = 0
Ey = k / (sqrt(1-v^2) *y^2)
So the field not lagging behind, it is simply length contracted in the direction of motion.
Why would the sensors be...
Let's say I've got a charged particle moving with constant velocity and multiple columns of electric field sensors parallel to its path. The sensors will trigger whenever a maximum passes by.
Will the sensors in a row be triggered at the same time? If they are, what does it mean for the field...
Once again, reactions are not perpetual. They will stop after reaching a new equilibrium. It doesn't matter if they are exo or endothermic.
Edit: With equilibrium here I mean chemical(reaction) equilibrium not the thermal one.
No. The endothermic reaction will draw thermal energy(heat) from the system to increase potential energy(chemical bonds). But there has to be an activation energy well for the endothermic reaction to happen. The difference between exothermic and endothermic reactions is that the latter will...
Exothermic and endothermic reactions are methods to create a disequilibrium. But they are not perpetual. You are sharing heat for chemical bond energy. You'll still increase the entropy of the system.
Dissipation can only occur if the system is in a disequilibrium. It will move the system towards equilibrium, increase entropy. In order for work to be performed/extracted there has to be some kind of disequilibrium(gradient).
Every solid body has a stiffness(resistance to deformation), can be approximated by a mass-spring-damper system, will have a resonant frequency. Resonance will occur if the external driving frequency matches the resonant frequency(or multiples of it/harmonics) of the body.
I am not an expert in this topic, but what you are trying to do is to solve a constraint matrix by linear approximation(thus jacobian).
Here is an example:
http://www.gamedev.net/community/forums/topic.asp?topic_id=512994
The force exerted on the road is equal to torque divided by radius for the no slip case (|T / r| < us * Fn). If you've got slip the force will be equal to kinetic friction. You would have to reduce the torque to get rid of the slip. There is no velocity dependency in this friction model...