Weird Definition and 469 Threads

G'day. I only have a lay interest in physics - I don't math or anything - but I think I get the jist of it. It's weird, huh?

If you have Clark, David, John and Steve in order and their last names (not in order) are Clarkson, Davidson Johnston and Steveston, where the difference in age between Clark and Clarkson is 1, the difference between David and Davidson is 2, the difference between John and Johnston is 3. What...

Hey guys I'm kind of stuck in this weird SULI situation and I've been sweating bullets since last night. I was contacted by an LBNL staff scientist who agreed to take me in. I received an email from him saying that he had accepted my application. I hadn't received an official offer yet so I...

Wikipedia says that superconductivity is a phenomenon which can only be explained by quantum mechanics. Maybe there is a close relation between the connection of superconductor parts and quantum entanglement? If yes, a question arises: what is the speed of electric current flowing through the...

Hi, as I know the barometric formula is an exponential equation, but when I did the experiment with a barometer at different heights and inserted these results in Excel for curve fitting, it showed a weird thing, I think. So exponential equation did show that R^2=0.942 and the second-degree...

This object, about the size of a tennis ball was found by my brother. It's metal. It's very hard. Cannot scratch it with a Stanley knife. Cannot break even a small piece off using pliers. Thrown with force at concrete and undamaged. Relatively heavy. My brother estimates similar weight to lead...

Hello! I am trying to align a bow-tie cavity and I noticed a behavior of the beam spot that I can't explain with my (limited) knowledge of cavities. For reference, I am scanning the current of the laser in order for the laser to follow the cavity. I attached below 3 frames from a video I took of...

Hello ! We all now that enzymes lower the activation energy by creating both covalent bonds and week non covalent bonds , in this book , about how the enzyme lower the activation energy using covalent bonds they said : this sentence is not compatible with a basic principle that i learned in...

Hi there. Let's say I have the following relationship: x = a + b*z + c*y z is distributed normally y is distributed according to a different distribution, say exponential Is there a way to figure out what is the distribution of x? Thanks!

Summary:: So apparently the equations schould be correct but I am not sure about it. Isnt R1 = Ub(10V) - Base voltage / Iq + Ib --> Ub is the source voltage 10V. And schouldnt R2 be :base voltage / Iq?

Hello, maybe you can settle an argument. The internet leaves people trying to spell words a little different, or creating new ones all together. For example, rocks, becomes rox, becomes roxor (said rocks-or) This leads to my question. ‘Boox’ is the ‘word’ in question. I think it should be said...

I need someone to check my work, because I'm getting weird results that I'm not able to interpret physically for parts b and c. Thanks in advance. For part a... ##J_u = e_1 \sigma_B T^4## ##P_1 = AJ_u = e_1 \sigma_B AT_1^4## ## T_1 = \left( \frac {P_1} {e_1 \sigma_B A} \right)^{\frac 1 4} ##...

I ran into an issue of expressing certain types of operators and after a little thinking managed to do it by decomposing them with the help of a weird class of functionals: $$|Φ⟩\rightarrowδ_{\{|Ψ⟩\}}(|Φ⟩)$$ for any state ##|\Psi\rangle##. And yes, it's a Dirac delta acting on the the Hilbert...

Hello! I am trying to measure the gaussian profile of a laser beam, which is supposed to be T00. The profile shown in the specifications looks very Gaussian, and the laser is brand new. I am using this camera and I am using 2 of these wedges to guide the laser beam into the camera (mainly to...

Hi all! I am new here :) I was observing Orion with the astro software Aladin and I found two similar relatively weird objects. I would like to share with you the image, with the zoom on each of them. Any explanation? Could they be the same object (a satellite?) seen in two different moments...

##\frac{d}{dt}P(x,t)=\frac{d}{dt}<\Psi|\Psi>## ##=<\frac{d}{dt}\Psi|\Psi>+<\Psi|\frac{d}{dt}\Psi>## By using ##\frac{d}{dt}=\frac{-i}{\hbar}H## , ##\frac{d}{dt}P(x,t)=<\frac{-i}{\hbar}H\Psi|\Psi>+<\Psi|\frac{-i}{\hbar}H\Psi>## ##=\frac{i}{\hbar}<\Psi|H\Psi> - \frac{i}{\hbar}<\Psi|H\Psi> = 0##...

Two things that I think I should say before I describe what I did: First, I do not have any physics-related background (but I have a degree in CS, and I'd like to think I have a good enough grasp on math to be able to understand equations describing motion of objects). So please forgive me if...

My book gives this formula for the semidirect product for groups ##Z_p## and ## Z_q## for primes p<q and p divides (q-1). ##(a,b)*(x,y)=(a+_q c^bx,b+_py)## There is also an explanation of what c is but very little else. It doesn't even explain what operation adjacency represents, eq...

Suppose someone doesn't have anyone to relate to on a variety of personal matters and just wants someone to talk to about those things. Would seeing a psychologist be a solution? Or, do they mainly see people with psychological issues? Also, what if a person is just feeling "lonely" or...

This is an interesting combinatorics problem that I thought of. Oddly, I think I know of an application of said problem to physics, but I could not find any problem like it online (the closest I got was the Knapsack problem, which is just about optimization). My initial instinct was to look for...

Hello all, Here's the deal. It's weird, but it's true. I will swear on "The Precious" if necessary. (gratuitous Ring reference) Due to the unique circumstances surrounding my life, I have lived in a major depressive with borderline personality traits state for the better part of 40 years...

The book is Calculus: Basic Concepts for High School on the first page you are given the following sequence: 1, -1, 1/3, -1/3, 1/5, -1/5, 1/7, -1/7, ... several pages later the rule is given: in the second rule, for the first term in the sequence, the coefficient of one of the terms is 1/0...

Logic and equations seem to have come out of nowhere in this question. I have been unable to understand where these equations come from and why they are used. Can someone describe the logic for the steps in the question?

I tried solving this, the equation coming up is given by: θ≈4 cot^(-1)(e^(-3.1305 sqrt(1/R) t)). However, this is not correct as can be seen when plotted: enter image description here Can somebody please let me know, why is this equation not valid.?

Problem: See Attachment. Parts (a) & (b) are clear, but my confusion arises in (c)-- I feel like there is a much simpler form. While technically my answer is correct, there must be something I'm missing. I parameterized the curve C=(t, e^2t, e^2t) and got c'(t)=(1,2e^2t,2e^2t), which should...

Would the A = 2.0 ms^(-5/2) affect my answers for parts (a) to (c)? Since I basically ignored the unit ms^(-5/2) and integrated the function to get the ones for velocity and displacement. And as for part (d) explain the dimensions of A; I assumed that the ms^(1/2) comes from the square root due...

I'm a bit confused about the condition given in the description of the symmetry transformation of the filed. Usually, given any symmetry transformation ##x^\mu \mapsto \bar{x}^\mu##, we require $$\bar\phi (\bar x) = \phi(x),$$ i.e. we want the transformed field at the transformed coordinates to...

Hello! I really don't know much about statistics, so I am sorry if this questions is stupid or obvious. I have this data: ##x = [0,1,2,3]##, y = ##[25.885,26.139,27.404,30.230]##, ##y_{err}=[1.851,0.979,2.049,6.729]##. I need to fit to this data the following function: $$y = a (x+0.5)/4.186 +...

How do you solve this kind of limit? \lim_{x \to ∞} \left( \frac{x^2 - 1}{x^2 + 2x + 5} \right)^{-2x} Please give me a clue.

Part of me thinks this is could be a u-sub b/c x^3's derivative is 3x^2, a factor of 3 off from what e is raised to...but it is not a traditional u-sub...any thoughts if this is a u-sub or by parts, and what u should be?I know that there is more to solving the equation after this ( z =...

Dear FEA experts, I’m trying to analyse* some finite elements model of a thin walled cylinder with variable cross-section, but I’m observing four weird issues in the buckling modes. The structure is vertically (along z-axis) and horizontally (along y-axis) loaded on top. Would you help me to...

Hello all: I have a small question about nuclear propulsion , why everyone are trying to use it ,and why this wired choice of nuclear option , retrofitting a nuclear reactor to mount it on the rocket , isn't that a little dangerous , why they don't use other option or research it , there is few...

As far as I know we can express the position and momentum operators in terms of ladder operators in the following way $${\begin{aligned}{ {x}}&={\sqrt {{\frac {\hbar }{2}}{\frac {1}{m\omega }}}}(a^{\dagger }+a)\\{{p}}&=i{\sqrt {{\frac {\hbar }{2}}m\omega }}(a^{\dagger }-a)~.\end{aligned}}.$$...

Hi, So,I'm helping a guy with his mechanical engineering homework. The problem is that the guy is so off, he doesn't even know the name of the subject. And honestly, I having a hard question finding out what this question is about. I need to proove the Zb=h^2/3 thingy. I have no idea what this...

So while I was trying to browse some notes with regard to Laplace transforms in solving systems of ODE, this matrix came up: I could easily just use RK4 and call it a day to nuke the systems of ODE, but this actually made me curious. Apparently one can transform the matrix DE into another form...

Hi everyone! I'm new to this forum, so I hope my question fits into this category. Yesterday I wanted to check if I could measure any radiation from Radon in my basement with my Radiascan-701 Geiger counter which features a pancake-style probe that should be able to handle alpha, beta and...

https://pmt.physicsandmathstutor.com/download/Physics/A-level/Past-Papers/AQA-Old/Unit-5/June%202016%20MS%20-%20Unit%205-2A%20AQA%20Physics%20A-level.pdf One question on this the mark scheme seems to skip this step as the intensity is Power per unit area , when you make I sun = I quaser *...

I remember that the definition of temperature is the average kinetic energy. Then how about if I keep shaking a box, wouldn't the kinetic energy of the box increase and thus the temperature of it increase? (neglecting the thermal energy gain from friction) Also, is it possible to use...

While I was going through "Introduction to Electrodynamics" by David J. Griffith I see the line "Current is a vector quantity". But we know it doesn't obey the vector algebra (addition ). Then how it can be a vector?... Please help me

Hi PF! I looked through the documentation on their website, but under the tab "Solve partial differential equations over arbitrarily shaped regions" I am redirected to a page that does not specify how to create a region. Any help is greatly appreciated. Also, if it helps, the domain is a...

I've seen the recent threads on this subforum about favorite songs,what you've learned,lame jokes...so,I decided to start a similar one. What are some of the weirdest science-related objects you've seen? If you posted a picture, please make sure it has no copyright issues and use a spoiler tag...

Homework Statement If the following question is inappropriate,please tell me immediately,and I will delete it.[/B] I got a really weird math homework today:find out questions in math textbooks of other parts of the world look like,specifically,how many percent of: prove questions(questions...

Not 100% sure this thread belongs in this section, sorry if it's out of place. I was trying to run a simulation of a 2D Ising model; i thought everything was going fine until I started to look at the numerical results and I noticed that I get some wild fluctuations in my results; as an example...

Sorry if this is in the wrong place. Sometimes I do really stupid things on integrals (use a method that gets me nowhere, make a mistake while factoring quickly, etc.) I have always been reluctant on using tables because I always felt stupid using them. I feel like I have to reinvent every...

Found this. What could it be? So many resistors and nothing else?

Hello all, I am trying to solve the integral: \[\int cot(x)\cdot csc^{2}(x)\cdot dx\] If I use a substitution of u=cot(x), I get \[-\frac{1}{2}cot^{2}(x)+C\] which is the correct answer in the book, however, if I do this: \[\int \frac{cos(x)}{sin^{3}(x)}dx\] I get, using a substitution...

Hi everyone So something strange happened tonight. I've always hung my night lamp on a hook in the wall but last night I kept it on the floor. And i saw fringes form on the floor (see picture) Could someone please explain why the fringes formed? My guess is that two different waves from two...

I had a thermos flask that I had never used since I had bought it. Today, I decided to take it out and use it for storing hot water, so that I don't have to heat water every time I feel thirsty. An interesting incident occurred. I heated water to near about boiling temperature, and filled the...

Homework Statement This problem showed up in my final review packet, and I /think/ it should be basic kinematics, but I don't even know how to approach it with the second half of it. An object moves according to the equation x = vt + ke^(bt), where k, v, and b are constants, x represents...