Dear Experts,
Currently I am reading up on Special Relativity.
I struggle to understand how from the perspective of the Muon that the distance to the surface of the earth is contracted and thus more Muons arrive at the surface based detector.
How can this be? To me the physical space is real...
Hi Folks,
Problem Statement
How would one use the conservation of angular momentum to explain the attached picture?
The rod is held fixed horizontally..the person holds on to the cork and then lets go...apparently the glass is saved due to this conservation...
Relevant Equations
Momentum...
Hi. I am not a student and this is not homework. I am reading physicsnin my spare time and occasionally I put a question up to get peoples opinions/help.
Please advise how I should proceed for future queries..
Thanks
B
Hi Folks,
How would one use the conservation of angular momentum to explain the attached picture?
The rod is held fixed horizontally..the person holds on to the cork and then lets go...apparently the glass is saved due to this conservation...
So in laymans terms if I was to describe a situation to my friend about stopping a 18stone rugby player in his tracks by a sufficient tackle..which would be more appropriate...the energy approach?
Or perhaps both are equivalent because to stop him covering more distance instantly is equivalent...
How should I look at the problem at stopping a moving object with the following conditions
1) mass m and speed v
2) 0.5 m and 2v
3)0.5m and sqrt 2 v
Simple math tells me the number 2 would require more energy to stop it. I can relate to energy better in terms of how to stop a moving mass...
Hi Guys,
I have a simple annulus of radius 25mm and 15mm of length 50mm where i applieD a torque of T=100000Nmm. Its inertia about its main axis is I=124.9 kgmm2.
Therefore i expect the acceleration to be T/I.
Its not clear how to confirm this answer in Msc Adams because when i set simulation...
but assuming we have the technology it would still be impossible to travel through all that dust without damage? To me, that is the ultimate limitation IMHO!
Hi Folks,
What is your opinion on this article? It suggest that interstellar travel is a fantasy.
http://www.scientificamerican.com/article/interstellar-travel-as-delusional-fantasy-excerpt/#
Yet, I read articles about institutions like NASA investing in various conceptual propulsion...
Hi Folks,
Can somenone explain what "information" is with respect to black holes?
I thought it was all about mass and energy from both quantum Mechanics and GR perspective.
Why does "information" come into it...sounds unusual to say the least.
Thanks
B
Hi Folks,
I am struggling to see how eqn 4.1.17 is arrived at using using eqn 4.1.10 at bottom of attachment. Its not clear to me what \frac{d \phi}{dt} is...apart from what is given in eqn 2.1.30...
Any ideas?
Thanks
I can say I fully understand but perhaps some one can enlighten me regarding what is involved converting derivatives to differentials....for my own understanding and information
Hi Folks,
I got stuck towards the end where it ask to derive the unit normal (eqn 3.2.29 I don't know how they arrived at n_x. I have looked at trig identities....and I have assumed the following
n_x=\frac{N_x}{|N_x|}
I dont see the (r+p) term anywhere in neither the top nor bottom.
PS: I...
Hi RUber,
I have it. The extended segment of "a" which forms a right angled triangle with P is Pcos(pi-psi). The tan of lambda is obvious. Thank you very much.
I have learned a new way of tacking triangles!
Folks,
I am puzzled how one obtains equation 3.2.31 based on the schematic as attached! Can you help?
Is there an online source I can refer to to learn how to obtain angles and magnitudes of complex schematics?
Thanks
Ah ok,
So I add in an extra step
wrt to x \phi_x+\phi_y \frac{dy}{dx}=0 *by dx to give \phi_x dx+\phi_y dy=0
or
wrt to y \phi_y+\phi_x \frac{dx}{dy}=0 *by dy to give \phi_y dy+\phi_x dx=0
Sorry, I understand the derivative of a constant is 0 but I still don't see how you get the last term where you have dx and dy by themselves...even if i try
\phi_x dx=-\phi_y dy= \frac{dy}{dx}=-\frac{\phi_x}{\phi_y}
Folks,
Differentiate implicitly \phi(x,y)=0 I get:
wrt to x \phi_x+\phi_y \frac{dy}{dx} and
wrt to y \phi_y+\phi_x \frac{dx}{dy}
however I dont know how this is derived
\phi_x dx+\phi_y dy=0
Folks,
What is the idea or physical significance of simultaneous diagonalisation? I cannot think of anything other than playing a role in efficient computation algorithms?
Thanks
Thanks for the video, very useful
I have expanded ##det(\Omega - \lambda I) = 0## to get
##\begin{bmatrix}1-\lambda& 3 & 1\\ 0& 2-\lambda&0 \\ 0& 1 &4-\lambda \end{bmatrix}##
For ##\lambda=4## say we get the following
##\begin{bmatrix}1-4& 3 & 1\\ 0& 2-4&0 \\ 0& 1 &4-4...