Can we do better than these general vague sentences to see how much longer than that it takes?
If you read my solution, you'll see that I already took into account that the Moon's period is not 1 month (I used 28 days), and that the Moon and Sun can be slightly more than 0.5 degrees by...
The result I get is 2 hours and 10 minutes. My reasoning is down here. But! Checking the map for the 2024 Solar eclipse, https://www.timeanddate.com/eclipse/map/2024-april-8, in many locations you can see a partial eclipse of over 2 hours 40 minutes. What is the main source of error here?
Here...
Is this expected? Shouldn't it be the opposite - if the extra mass is negligible, non-slipping should be easier I'd say?
I get a slightly different result. The calculation is quite messy, not sure if you found a quick way to do it. I'll try to keep it short. Angular velocity after impact was...
(This was an answer to a post that has been deleted and suggested checking for non-slipping just during the collision)
I interpreted it as requiring the non slipping condition to be true during the entire motion, not just right after the collision
This problem is hard. It found it listed among problems discussed in a classical mechanics course for physicists at the university of Pisa and don't have a full solution. It's not 100% guaranteed that there's a nice close-form solution, but probably yes; and if not, there should be some trick to...
Thank you. I thought about it for a while and I agree.
I haven't been solving PDEs for a long time. Could the 1 dimensional heat equation with this type of BC be solved by standard techniques?
Homework Statement
A cup of hot chocolate of radius r and height H is completely full. The density ρ and specific heat C of chocolate are known. The cup is very well insulated so that heat is only exchanged with the outside room from the open top. The chocolate is initially at temperature T0...
Homework Statement
A fluid of viscosity \nu is rotating with uniform angular velocity \Omega inside a cylinder of radius a that is also rotating. At time t = 0, the cylinder is brought to a rest. The circular motion of the fluid is gradually slowed down due to the viscosity; show that u_\theta...
Hoping someone finds this problem interesting, I'm looking for some ideas on how to solve a real world problem, not a complete and detailed solution. This topic is related to an astrophysical situation. However, I prefer to present it just as a question on gas dynamics since there's no need for...
[where is the "itex" button? Do I have to write itex and /itex by myself every time?]
The radial Lorentz force is (signs depend on the orientation of the vectors and I'll never care about them in the equations, and I'm doing this in MKS this time) F(r) = eBwr. Hence EMF = \int F(r) dr / e =...
Homework Statement
A cilindrical copper disk (radius R, thickness a) at time t=0 is spinning around its axis with angular speed w in a uniform magnetic field B parallel to its axis. The edge of the disk is connected to the center with a "wire" which we assume to have negligible resistance and...
I'm sorry i can't quote the right parts of your post but I'm writing from a smartphone. I didn't know the fusion stopping time scale was bigger than KH, I'm sadly weak in Nuclear physics.
I don't understand why the gravity rises just before the collapse starts. Where does the new
mass come...
Ok but you still didn't tell why the pressure drops in a short phase. This is really important because this is what allows the collapse to start.
If it's not because of the radiation pressure, I think the reason might be the following: when the fusion reaction stops, the equilibrium in...
Yeah, ok, I meant that less photons are produced. My fault.
Then why does the core start to contract? "There's less energy so it contracts" isn't a dynamical explanation, we need to find out which pressure source (radiation, ions and electron gas, or whatever) starts to drop.