# Search results

1. ### Centre of Mass of a Uniform Cuboid -- Show that it is at the Center

Yeah, if I did this question I would naturally distinguish between those two but I never asked myself why that is fundamentally the case.
2. ### Centre of Mass of a Uniform Cuboid -- Show that it is at the Center

Yeah. I solved a lot of integrals. I know I need to distinguish between ##V## the volume and ##V## the integration parameter. I just never asked myself why you fundamentally have to do it.
3. ### Centre of Mass of a Uniform Cuboid -- Show that it is at the Center

Yeah yz is the constant cross area
4. ### Centre of Mass of a Uniform Cuboid -- Show that it is at the Center

Well I am going from x1 to x2 but it's all multiplied by yz
5. ### Centre of Mass of a Uniform Cuboid -- Show that it is at the Center

So, I volunteered to run a seminar to first year students in my college. They got a question like this for homework recently and a lot of them made a mistake in the calculation. I am not asking for help with the question itself because I know how to do it. However, a lot of students made a...
6. ### 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...
7. ### Physics Internship possibilities: Plasma physics

Thank you. I will look into it.
8. ### Plasma physics project ideas

That's alright. I'll definitely keep that in mind when choosing a project. Thank you for the help.
9. ### Plasma physics project ideas

Yes, but I reckoned there would be no point in doing a project on a topic I know cause I'm not learning anything new that way.
10. ### Physics Internship possibilities: Plasma physics

Hi guys. I'm a third year physics student. Next year I'll be in my final year. I'm interested in studying fusion in the future. Unfortunately I have not done plasma physics as part of my degree so I don't know much about it yet. However I'd like to do an internship abroad this summer. Ideally I...
11. ### Plasma physics project ideas

Summary:: I am looking for topics to give a presentation on. Hi everyone. If this is in the wrong section feel free to move it. Anyway, as part of our lab course, on top of doing experiments we will also have to prepare a 20 minute presentation on a chosen topic on physics. This is not like...
12. ### 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.
13. ### 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...
14. ### 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
16. ### 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}...
17. ### 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.
18. ### 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...
19. ### 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...
20. ### Magnetic field outside a solenoid

I attempted it but I wanna ask whether I'm going about it the right way: Also is the enclosed current angle always dependent? On one hand we have that: ##\oint####B.dl=####\mu_o####\int####J.da## Which reduces to: ##\oint####B.dl=####\mu_o####I## The first equation is a dot product...
21. ### Magnetic field outside a solenoid

In his book on electrodynamics, Griffith talks about the magnetic field outside a solenoid. Firstly instead of dealing with a typical solenoid with closely wound loops, he instead works with a cylinder with a surface current that has no z-component. To get the angular component of the B-field...
22. ### I Numerical solution to the Schrodinger eqn. using Finite Difference Method

As part of my project I was asked to use the finite difference method to solve Schrodinger equation. I see how you can turn it into a matrix equation, but I don't know how to solve it if the energy eigenvalues are unknown. Are there any recommended methods I can use to determine those...
23. ### Energy of a crystal in thermal equilibrium

Homework Statement In a monatomic crystalline solid each atom can occupy either a regular lattice site or an interstitial site. The energy of an atom at an interstitial site exceeds the energy of an atom at a lattice site by an amount ε. Assume that the number of interstitial sites equals the...
24. ### ∆KE if angle between force and displacement varies

Or it can also be expressed as cos inverse of x/√x^2 +1.3^2
25. ### ∆KE if angle between force and displacement varies

I suppose the angle can be expressed as Tan inverse of 1.3/x
26. ### ∆KE if angle between force and displacement varies

It is displaced in the negative x direction and the force in that direction is negative 25cosA
27. ### ∆KE if angle between force and displacement varies

It's the dot product of the two
28. ### ∆KE if angle between force and displacement varies

Its the transfer of energy to or from an object due to the action of a force.
29. ### ∆KE if angle between force and displacement varies

Well they are equal to each other. Im just not sure how to calculate the work done
30. ### ∆KE if angle between force and displacement varies

Homework Statement A string is attached to a block that can slide along a frictionless horizontal surface aligned along the x axis. The left end of the string is pulled over a pulley of negligible mass and friction at a height of 1.3m so that the block slides from x1=3m to x2=1m. The tension...