Confused — 400 discussions

Following the above statement my teacher was trying to prove something and it started with suppose q1 and q2 are charges placed in a medium (k) of infinite expanse. The distance between them being r. He took q1 and q2 to be some spherical particles and not point charges and concluded that Net...

Hii, I am of +26 years old. I am confused whether I should pursue PhD in India or look for research jobs. I like to read but I am not meticulous smart, I get confused easily and things doesn't make sense to me easily until I put my extra efforts. Kindly help me to choose a career trajectory. I...

hi, I am a physics student in grade eleven. I do not have much knowledge of physics but I have a doubt: apart from the maths and the experiments, shouldn't larger masses be attracted to Earth's gravity rather than be attracted the same regardless of mass? if we had a scenario where we have...

Hi, PF Integration by parts is pointed out this way: Suppose that ##U(x)## and ##V(x)## are two differentiable functions. According to the Product Rule, $$\displaystyle\frac{d}{dx}\big(U(x)V(x)\big)=U(x)\displaystyle\frac{dV}{dx}+V(x)\displaystyle\frac{dU}{dx}$$ Integrating both sides of...

Hello! I am building a bow-tie optical cavity, of finesse about 10,000. When I measure the transmitted signal out of the cavity, after aligning it, I see clear peaks, significantly higher than the background and pretty much single mode. I do see 2 other peaks, probably from other modes, but much...

Hello! I have 2 probabilities ##p_1## and ##p_2## which governs the probability of measuring some events. I measure event 1 N times and get ##N_1## counts and event 2 N times and get ##N_2## counts. Then I need to build the function ##A = \frac{N_1-N_2}{N_1+N_2}##. I am trying to estimate the...

Hello! I am trying to simulate the following experiment. It is a counting experiment where the probability of getting an event after a given trial is given by: $$P = 2\left(\frac{a}{x}+\frac{b}{c}\right)^2\left(1-\cos\left(\frac{\pi x}{x_0}\right)\right)$$ where, ##a = 4\pi##, ##b = 2000\pi##...

I keep running into the issue of getting a different number of significant figures in my solutions than the official answers at the back of the book, so I'm wondering if I'm missing something or if the book is occasionally sloppy about significant figures. In Unit 1, the book states (p.8.)...

TL;DR Summary: I approach a rocket acceleration problem using two approaches: F=d(m*v)/dt and F=ma. The resulting differential equations are different. What am I doing wrong? We have a ship with a mass-reaction rocket engine floating in space. The initial mass of the ship (including fuel) is...

Hello! I have a 2 level system given by: \begin{pmatrix} 0 & A \\ A & Bcos(\omega t) \end{pmatrix} If I populate only one of the states initially, at ##t=0## the 2 states are B apart, while after half a period they are -B apart. Basically the system went from one side of the avoided crossing...

I have the equations to calculate transmission probability, my problem is that the barrier is given in Volts not electron volts. $$200V = e \cdot 200 eV = 3.2 \cdot 10^{-17} eV$$ I am not even sure if that's a correct conversion. But if it is then this "barrier" is extremly small and 99.999%...

For this problem, I don't understand why they are saying ##-1 < a < 1## since they are trying to find where ##f(x)## is continuous including the endpoints ##f(-1)## and ##f(1)## Why is it not: ##-1 ≤ a ≤1## Many thanks!

If the speed of light in the vacuum of empty space is the same for all observers, how can there be a Doppler effect on light? Doesn't the shift of color/frequency indicate a change in speed? Sorry if I posted with the wrong prefix, I'm just a curious senior (as in old guy) :oldconfused:

Hi all, I'm a bit nervous about the implications of relativity, not the block universe stuff I can work with that.. What worries me regards planes of simultaneity, when I'm walking away from you my plane of simultaneity will contain you from your past, so the you in my reference frame...

So I want to subtract the two surfaces, right? I really don't know where to start... I am guessing this would be some sort of triple integral, however I am very confused with the bounds. Any help would be greatly appreciated! Thanks!!

Hello, I've bin the mid of my Msc in physics preparing for gate/ net exam 2023. I don't know which stream to choose for research. I am highly highly interested in solar energy, green energy and mechanical engineering as well but I don't know what to do as I am not an engeenering student. I...

I'm not sure where to start, I feel like I'm missing the mass but it is not listed.

im confused about the difference of this equation: and this one: which gives percentage uncertainty, so which one should be used to calculate the uncertainty?

Tried making many squiggles, I don't understand the concept of finding a distance or position based on a time for part of the flight. I have 2 other similar questions and I haven't been able to make any progress on any of them. I attached a photo of my scribbles, which are all obviously...

Background. Trying to lose weight via a clamp down on carbs so I decided to try sachet soup for lunch at work. mostly water, not many calories. Examining the contents some of the wording is confusing. Total Contents 81g = 4 sachets so 4 "meals" I weighed one and it was approximately 20g so...

I refer to the tables on https://en.wikipedia.org/wiki/DNA_and_RNA_codon_tables In both the DNA and the RNA codon tables, ACG codes for threonine. But the transcription of the ACG from the DNA to the mRNA ends up with UGC (which would code for Cysteine). So should I assume that when the DNA...

I presume that the sphere is pointing at the declination of -90, and that the descriptions "torrid" & "temperate" correspond to tropic & non-tropic, respectively; as such, it seems that these descriptions are on the wrong sides...

Hi I am reading a book and I am confused why some text is mentioned. Could someone help explain. https://scholar.harvard.edu/files/david-morin/files/relativity_chap_1.pdf page 14 " There is always a difference between the time that an event happens and the time that someone sees the event...

here is what i wish to say. basically i am a 23 year old guy who has wasted a lot of time not finishing any course i started and also occasionally trying to be a musician but also did not fully get into that. There were times since completing high school that I found myself very intersted in...

The k-th Pontrjagin class of a real vector bundle is defined as the 2k-Chern class of the complexified bundle. Therefor, a Pontrjagin class lives in cohomology with integer coefficients. But then the statement of Theorem 15.9 is that if the coefficient ring is taken to be a PID \Lambda...

Hello , i am a little confused about this exercise because we talk about gases reaction and we are asked about the concentrations P.S : i have other questions that depends on your answer . Thanks .

the answer is attractive. but i don't see how this is how I draw mine and I use the RHR on the magnetic field between the two wire and I got the force is opposite

I am not sure what I am doing wrong but dot product of a and b =/= |a||b| when I am trying to calculate it. Theta = 0: dot product(a and b) = ax*bx + ay*by |a||b|= sqrt((ax^2+ay^2)*(ax^2 + by^2)) = sqrt((ax*bx)^2 + (ax*by)^2 + (ay*bx)^2 + (ay*by)^2) =/= ax*bx + ay*by What am I doing wrong?

If there is a car resting on a banked curve with angle theta, velocity v = 0, but N (normal)*sin(theta) > 0. So N*sin(theta) =/= (m*v^2)/r with v = 0. But my physics textbook just defined N*sin(theta) = (m*v^2)/r in banked curve. What is going on here?

I was watching this video that I found on Youtube. My question is, does type of electrolyte affect the voltage reading, since it dictates which redox reactions are possible? (here, Na2SO4 instread of CuSO4) Consider a Mg|Cu electrode pair in a galvanic cell; the reaction is, usually in...

It is asking to derive the time-independent wave function and has managed to get the answer of and i am very confused as where (ix/a) and (-x^2/2a) came from ? Thanks.

I tried a web search but how this immunity stuff works with chicken pox, shingles, and the vaccination I cannot understand. Person can suffer chicken pox infection from the virus, recover, and later be vaccinated (at least age 50) with Shingrix vaccination, to be protected. But the virus is...

# Python dictionary to act as an adjacency list graph = { '7' : ['19','21', '14'], '19': ['1', '12', '31'], '21': [], '14': ['23', '6'], '1' : [], '12': [], '31': [], '23': [], '6' : [] } visited = [] # List of visited nodes of graph. def dfs(visited, graph, node): if...

The DFS in action doesn't relate to the pseudocode as you can see it. My confusion starts from dfs in action, step 4. I could write essay about it, but you can see it yourself as well and spot that algorithm and dfs in action doesn't match up properly. or is it only me? This is not a homework...

Hi! The problem clearly states that there is a surface charge density, which somehow gives rise to a potential. The author has solved the Laplace equation in cylindrical coordinates and applied the equation to the problem. So ##\nabla^2 V(r,\phi) = 0##, and ##V(a,\phi) = V_a(\phi)## (where...

I'm trying to understand Newton's third law in the context of collisions. Assume that one body has mass M kg and is traveling in the positive x direction with acceleration A m/s^2. Assume that the second body has mass m kg and is traveling in the negative x direction with acceleration a m/s^2...

I am confused by the concept of space-time in special relativity, I have 3 spatial dimensions and 1 time dimensions. In Newtonian physics don't I also have 3 spatial dimensions and 1 time dimension? Then why call it space time in special relativity and not in Newtonian physics?

I am going through this notes, i can follow quite well...my only issue is on the highlighted part...i thought that we had two boundary conditions for ##y## ( of which one of them is non homogenous) and two boundary conditions for ##x##( of which both are homogenous)...kindly clarify on this part...

I want to find difference between two list. I came across sth called list comprehension. I can't tell you how confused I am with this. # Python 3 code to demonstrate # to remove elements present in other list # using list comprehension # initializing list1 list1 = [1, 3, 4, 6, 7] #...

I'm now learning about rotational motion without slipping and it's really hurting my brain to think about. Imagine a cylinder rotating on a flat plane. I can accept that there is both translational and rotational motion. For example, a given point on the circumference of the cylinder follows a...

Hello, in one of tasks of my liquid scintillation lab is to determine the average energy. You can see from the graph that data I obtained is similar to this one that I have a excel sheet data. X-axis is for beta particle energy from 0-156keV while y-axis counts of the particles. So according to...

Summary:: confused in program. Write a while loop to display each character from a string and if a character is a space, then don’t display it and move to the next character. Use the if condition with the continue statement to jump to the next iteration. If the current character is space...

(I Didn't use code formatting here as I felt it was not necessary) I have read multiple textbooks, articles and watched multiple videos about name binding in python. Till now what I understand can be summarized in this-: x=1 means name x is binded to object "1" z=x and we know x=1 => z=1 so...

(I Didn't use code formatting here as I felt it was not necessary) I have read multiple textbooks, articles and watched multiple videos about name binding in python. Till now what I understand can be summarized in this-: x=1 means name x is binded to object "1" z=x and we know x=1 => z=1 so...

[Moderator's note: Thread spun off from previous thread due to topic/forum change.] Time dilation sounds really weird, can i assume it has a logical explanation?

Most of my questions are from these articles: https://www.google.com/amp/s/www.sciencealert.com/if-you-thought-quantum-mechanics-was-weird-wait-til-you-check-out-entangled-time/amp https://www.scientificamerican.com/article/how-einstein-revealed-the-universe-s-strange-nonlocality/...

So I have a trolley of mass m that moves on a straight line. A sphere of mass m, is attached on the trolley with a light string of length a and it is left to oscillate. Just to give some idea of their positions: r_trolley = xi r_sphere = (x-asinθ)i - acosθj (θ is the angle between the string...

They seem to be similar terms, although elevation & altitude seem to be the exact same thing. AIUI, the declination of astronomical object refers to the latitude on Earth where it is at the celestial zenith - i.e., straight up, along the line from the Earth's center and surface at such zenith...

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Sketch by hand the function determined as f(x) = 1/28 (7√−16x^2 + 16x + 5 + 12) and then From the sketch, determine the domain and range of f in interval notation. Hint: Interpret f as part of a circle. You must include in your solutions the inputs and outputs you used to help you sketch the...