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1. ### Numerically simulating stellar pulsation using a "one zone" model

The question is taken from An Introduction to Modern Astrophysics by Carroll and Ostlie. I did manage to do the entire question and plot the relevant graphs but I just wanna to investigate a bit more. For example I wanna look at how the graph would like in the case of the Sun. I don't know what...
2. ### Stress tensor for a parallel plate capacitor

Ah okay, so all the momentum will go straight into the plates. I think I understand now. Thanks a million.
3. ### Stress tensor for a parallel plate capacitor

Okay that is starting to make more sense now. Just need to clarify a few small things. There is no magnetic field in the question. Therefore the Poynting vector is zero everywhere. So the volume integral of our Poynting vector will be zero. Therefore the electromagnetic momentum at any point in...
4. ### Stress tensor for a parallel plate capacitor

Region II is gaining z-component of momentum and region I is losing z-component of momentum

Negative
6. ### Stress tensor for a parallel plate capacitor

So I read the chapter more carefully and I'll try these again (a) The quantity ##\left(-T_{zz} \right)##: given a surface (in this case x-y plane) oriented in z direction, the z component of momentum flowing through the region (b) -##\sigma^2/2\epsilon## (c) The quantity ##\left(-T_{zz}...
7. ### Stress tensor for a parallel plate capacitor

That would be the z component of the electromagnetic momentum to be more precise. I think if the quantity ##\left(-T_{zz}\right)## is positive the direction would be downward.
8. ### Stress tensor for a parallel plate capacitor

(A) That's the electromagnetic momentum flowing through that point in the xy plane (B) You could use the relationship between force and electric field i.e. force per area is the electric field times charge density (C) It is positive (D) In the same direction as (C) (E) The region above xy plane...
9. ### Stress tensor for a parallel plate capacitor

The question is partially taken from Griffith's book. I am confused about the physical meaning of momentum in fields. I have determined the solution and found that in part d the momentum crossing the x-y plane is some value in the positive z direction. I don't however understand the physical...