Confusing Definition and 407 Threads

Hello all, I am currently studying for a physics a-level qualification in the UK, I use the AQA specification and I am having trouble understanding this image representing a scenario I found in my textbook. The first image in the three part diagram shows this rotating coil and to me, it makes...

R=(01+010)* For it I made the below nfa which i believe seems correct. Plus the tutorials that I am following also make sure it’s correct. Q0 is initial state(forgot to mention in figure). R=(01)*+(010)* But idk how to convert this to NFA What will be languages accepted by this NFA? Won’t...

I have great difficulty understanding the solution. I'll go through it line by line: c boys can mow a acres in b days. This condition is from the problem and I understand it. 1 boy can mow a acres in bc days. Why not b/c days? After all isn't 1 boy from c/c=1? n boys, or 1 man, can mow a...

This situation is really confusing me. First of all, does accounting compressibility affect the measurements for CL? If yes, how does CL change as a function of the increasing mach number? Back to the problem, above is the "in-flight" lift curve for a plane traveling at high speeds, so the CLs...

If the book had said that electrical potential energy is the negative of work done by electrical force on a charge, then the definition would be very clear and easy to understand. So, why should the book give this confusing definition instead.

The problem is a classical one, basically to find the equations of motion of cylinder of radius a inside a fixed cylinder of radius b, the cylinder that rolls rotate about its own axis in such way that it does not skid/slip. Now, the thing that is making myself confused is the constraint...

Hello , I don’t think enthalpy makes sense, I am here because I want a clear explanation for what it really is. It has been said it is the internal energy and the volume it takes as in work (W) but why? Why do we even need enthalpy what is the problem with delta U! It is equal heat and...

In Griffiths Quantum Mechanics 2nd edition, in Chapter 8 he calculates the following integral on page 323 and he gets I disagree with this result, I think the integral should be since Maybe somebody can explain why I am wrong? Also, from equation 8.24 to 8.25, he makes the assumption that...

Dear all, We learn students to work with significant figures. I guess we all know those rules of thumb. Now imagine I have an expression like L = 2x, where x is a length a the 2 is an amount, i.e. the value of a discrete 'function'. If x=0,72 m (2 significant figures), then L = 1,44 --> 1,4 (2...

This is the question: This is what I did. I have no other idea what else I can do to solve this confusing problem.

I know that (1/2)m(u^2) is KE and initially I thought this showed PE=KE but I don't think so anymore... I believe this has something to do with acceleration and Centripetal force but I'm so so confused

Now I don't really know much about the subject, I'm primarily just peaking into my textbook to see how to solve this or that exercise. I believe I can figure out how to solve the third question. However I couldn't find how to solve the first two. I know how to find a 95% confidence interval for...

In my opinion, the voltage across the C1 should be 9V as the potential on the side of the positive plate of the capacitor should be (15-6)V and on the other be 0V. Similarly the potential across C2 should be (7-0)V. Here I'm basically assuming that the voltage at the negative terminals of the...

Bartlett’s Calculus Paper Reviewed in Mathematics Magazine https://mindmatters.ai/2020/03/bartletts-calculus-paper-reviewed-in-mathematics-magazine/

I noticed that I posted this question on the wrong section previously by accident and I don't know how to delete it... Sorry for confusing the two sections====== Given: - A sticks to B - B doesn't stick to C My solution: As A sticks to B, one must be a magnet and the other iron. As B doesn't...

Not sure how they obtained an answer of (2meukenetic *Mg/R^2)*r^2 dr = dt When they say disk I am assuming it's not ring shaped. So since F * Dr= DT where I guess F acting on a small point on the disc is constant from the table top. And Dr is the variable distance from a random small point from...

A gear A has 50 teeth and another B has 10 teeth, how many times does the small gear rotate around the big one? I thought 5 but its 6! Note: The gear is curved like 360 degrees.

Summary: Confusing Inductor question I've been in trouble with a question for whole days , trouble is finding parts b,c and d. ------ in the solving of part b WHEN we find i0(t) ,why minus is in front of integral(-1/4 coefficient one) and why +5 why not -5 ? I think it relates passive...

Kindly don't delete the post again, I am a teacher. The question above mentioned came in Board Exams 2 years ago in our Country. We the group of teachers tried to solve but we found that the problems misses the required information to be solved. The data still seems to be the case of Doppler's...

Hello! It says that the Time Constant of an RC circuit is equal to 100 ms. What is the energy that remains in the circuit after 300 ms? "Nothing mentioned about whether it is in falling or rising edge". The formulas that I have been using are : W = 0,5 (C* V^2) V = V0 ( e^-t/rc ) since I don't...

Something occurred to me that doesn't seem to make any sense to the way I understand physics. Perhaps someone can explain it. Riding a bicycle on a descending road on very rough pavement and coasting I came to a flat and they had repaved it and it was perfectly smooth. My understanding of...

Consider a potential cavity $$V(r)=\begin{cases}\infty, &x\in(-\infty,0]\\\frac{\hslash^2}{m}\Omega\delta(x-a), &x\in(0,\infty)\end{cases}$$ The eigenfunction of the wave function in this field suffices $$-\frac{\hslash^2}{2m}\frac{d^2\psi}{dx^2}+\frac{\hslash^2}{m}\Omega\delta(x-a)\psi=E\psi$$...

I came across the following working in my notes and would like some help understanding how the step was done. Many thanks in advance! The following is the working, and we assume that ##\beta## is small $$\frac{1}{1+ \beta \hbar \omega /2 + (7/12)(\beta \hbar \omega)^2 +...} \approx 1 - (\beta...

Hi I have the following situation: (Please see attached pic) I want to know if equation (4) i have written is correct. What is confusing me is that, I remember being told in circuit analysis that each energy storage element should have its own state variable. But in this situation when I...

Homework Statement It’s a rather confusing circuit, I’m having problems trying to understand the way current circulates through the circuit. Homework Equations Kirchoff’s DC circuits laws only, no resistive simplification neither nodal analysis The Attempt at a Solution I’ll attach my intent...

\sqrt{\sqrt{}}Firstly, I have tried to work out the square root sign, I would have thought this common sign to be listed on the right. While checking my answer to the square root of 171 I noticed wolfram displayed also another function under the listing of "exact answer". It gave 3 with a...

I'm taking physics for the first time, and I've been attempting the textbook problems, but I can't seem to get it. 1. West stands on the roof of a building, leans over the edge and drops a rock. Lindsay waits 1.25 s after West releases his rock and throws her own rock straight down at 28.0...

Hi, There are two particular scenarios involving entanglement that are confusing me. For both of these, assume we have an electron-positron pair created from a spin-0 particle, in which all components of spin must be opposite in order to conserve angular momentum. The electron and positron are...

I am not a teacher, but I have made an interesting observation regarding classical mechanics education. It is surprisingly common that even students at academic level do not seem to fully understand Newton's third law (action and reaction) and confuse it with Newton's second law...

Homework Statement What mass of iron(3) chloride should be added to 450 ml of 0.132 M CaCl2 to give a solution with final chloride concentration of 0.555M There are a lot of numbers, and I get confused on how to convert it to get mass of iron(3) chloride! Homework Equations M = n/L The...

hell out of me :( please help: I have a Haynes manual for my motorbike and am trying to make sense of the wiring diagram but it's really annoying me why there are no legends apart from the wiring, no explanations of the tables etc, Every paragraph is referring to the image directly above it...

Hi there, I have this performance task on Math and I'm struggling with this Venn diagram problem. 50 Grade 6 students were surveyed on their favorite types of kid-friendly content on Youtube. 17 liked Gaming Videos only, 6 liked Gaming Videos and How-To videos, 2 liked How-To and Comedy...

It seems like the following sentence implies that 'dark energy' *(assuming that is the cause of the acceleration) is infinite: "the universe appears to be expanding at an increasing rate,[1] so that the velocity at which a distant galaxy is receding from the observer is continuously increasing...

From time to time I come across some text in a Wikipedia article that is quite misleading to a naive reader. The following is an example: https://en.wikipedia.org/wiki/Friedmann_equations The problem is that the sign of Ω0,k is backwards. That is the sign is positive for a universe with...

Hi all, I encountered a fairly straightforward problem involving fluid dynamics, but the result I got is very confusing and I seem not to understand where I got wrong. This is the question: A rectangular flat-bottom barge with a bottom area A=50 m2A=50~\text{m}^2A=50 m2 is loaded so that the...

Ok, so here's another example Morin did in his book: Ok, so the thing that confuses me is when he used the velocity addition equation: Note:4c/5 and 3c/5 are their speeds relative to the ground. Where v2 is the velocity of the S' frame, and v1 is the velocity of the object moving in the...

I have tried to find the least confusing (or rather, the most 'deconfusing') explanation for why it is possible for a cart with a prop to travel directly downwind faster than the wind. So far this is what I've come up with: Initial discussion At first glance, a cart traveling down faster than...

Homework Statement The circuit in the figure below has been connected for a long time. Let R1 = 8.20 Ω and R2 = 4.40 Ω. (a) What is the potential difference across the capacitor? (b) If the battery is disconnected from the circuit, over what time interval does the capacitor discharge to...

Homework Statement Homework Equations Please review the question and answer of question 34. The Attempt at a Solution 1.Why does the answer take the rated power as the power output? 2.I tried to find the current like this: R=200^2 / 100 = 400 ohm I at Q = 400/[2(400)] = 0.5 A I at P = 0.5/2...

Consider a man having superpower,weighing 70 kg jumping from moon to reach Earth in 10sec..what's the speed at which he travels..considering gravity etc...

I am learning principle of optics written by Born&Wolf and confused with the method to derive Snell's laws and law of reflection. In the textbook,##v_1## is the speed of light in mediator 1 and ##v_2## is the one in mediator 2. ##{\vec s}## is the direction of light and ##{\vec r}## is the...

I was thinking about triple nested for loop with a simple thought exercise on my own. I was little bit confused about that third nested loop (print c loop) With simple case of double nested loop, I think I understood how the program works. (only one nesting). But I'm having some trouble...

I'm reading Thermodynamics: Foundations and Applications by Gyftoploulos and Beretta, because the authors claim to give a presentation of classical thermodynamics without "... the lack of logical consistency and completeness in the many presentations of the foundations of thermodynamics" [from...

Hi all, I have a difficulty to understand the concept of phase velocity of a wave packet. I read some materials online and my text, I didn't find a very straightforward explanation on this concept except the math definition. I also read some threads from this forum, but still have some...

Homework Statement Charge q1 = +8.36 μC is fixed at the origin and charge q2 = -4.28μC is fixed on the +x-axis, 0.371m from the origin. (a) Find the direction and magnitude of the electric field at a point P that has coordinates (0.466, 0.466) m. (b) Find the direction and magnitude of the...

Good afternoon people. Recently I started taking a course at my college about Fourier series but I got extremely confused. Here's what's going on. In school we were asigned to use the symmetry formulas to find the Fourier series of the following: f\left ( t \right )=\begin{cases} 1 & \text{ if...

Homework Statement \lim\limits_{x \to 0} \left(\ln(1+x)\right)^x Homework Equations Maclaurin series: \ln(1+x) = x - \frac{x^2}{2} + \frac{x^3}{3} + ... + (-1)^{r+1} \frac{x^r}{r} + ... The Attempt at a Solution We're considering vanishingly small x, so just taking the first term in the...

I have a word problem to solve and am thoroughly confused. any input would be great... My younger brother had a run in earlier with Médecins Sans Frontières. He narrowly escaped from an adverse verdict by the court... What he wants is that he be left alone to run his small café... He asked...

OK, so I've gone through probably 90 tutorials on electricity and related topics, and there's a bundle of terms I ran into, used by people ages 12-80 with a dozen different accents and twice as many time zones. (So I'm not sure how many terms are universal and how many are provincial). Live...

Homework Statement A 975 g block is released from rest at height h0 above a vertical spring with spring constant k = 410 N/m and negligible mass. The block sticks to the spring and momentarily stops after compressing the spring 24.2 cm. How much work is done (a) by the block on the spring and...