Hard Definition and 1000 Threads

Why is it hard to get the air through the balloon when you first fill the balloon ? But after inflating it z bit it becomes easier to further inflate ?

https://www.youtube.com/watch?v=8GQZuzIdeQQ

It's just this one class I'm taking. It's really, really demoralizing. I normally do pretty well in my classes, I'm majoring in electrical engineering and I've so far kept a 3.2 GPA. I've only had to repeat one class, calculus II, and that was over a year ago, all of my other math classes I...

Hey and thank you in advance for taking the time to read and hopefully replying to this. I have been doing a lot of research into becoming a mechanical engineer the past few weeks and this is sort of the last step for me in deciding whether or not to apply to the schools and commit to it. I...

In reading some stuff on this forum and about general math education in the US at least, I'm curious as to others' experience with math and when it "got hard" for them. People here I assume are mathphiles and love math. They've done well, math came easy, etc. I include myself in this category...

Hi guys. Consider the problem of calculating the multiplicity (phase space volume) of N hard sphere gases each of whose center of mass is confined to a volume V. The spheres themselves have volume ##\omega## and do not interact with one another in equilibrium time scales. Then ##\Omega \propto...

For the diagram overleaf solve the problems by at least two different methods. Firstly use you knowledge of the equations of motion for motion under gravity where air resistance is neglected. Secondly, knowing the shape of the curve, find the relationship between height and horizontal...

1. All given variables and known data Consider a particle of mass m subject to the infinite square well potential function (with L>0) Suppose that you do not know the state function describing the system, but that you are told the expectation value of the position of the particle is...

Hey all. I'm getting a new hard drive in tomorrow and I was wondering if there was any software that would copy everything from the old hard drive to the new one without having to re-install windows. Any ideas? (Or other methods of keeping all of my current data and settings in windows on a...

I want to output a specific wavelength of infrared light, I believe the wavelength was 9.25nm, how hard would that be and how would I proceed?

I know it depends from person to person,,, but what's the estimate? I remember someone posting(I don't remember who) that relying on intuition to solve problems is a bad habbit. It just means that I'll have to start studying from the scratch? Let's say I want admission in one of the top 100...

Please don't say this is homework because it is not. I am simply studying problems for the physics c exam and I can't figure out this textbook problem. Please show me how to do this! The equivalent resistance part in the most depth because I don't understand. Is it right to say no current...

While I enjoy space opera (Star Trek, Star Wars, etc) my favorite fictional genre is the rarer hard science fiction, stories that involve science and engineering which doesn’t yet exist, but, unlike soft SF and fantasy, don’t can be rigorously explained as possible by present-day science, making...

Hi all, I have a few doubts and qualms regarding general physics, and how it seems that it will get quite difficult soon... So I've been learning lots over the past two or so years, and usually haven't had much trouble with the physics or math part of learning. I've learned classical...

Hey! It is the first time I post on this subform. Please forgive me if I do something wrong. Homework Statement F(x)=\int^x_0f(t)dt for R \in t \rightarrow f(t) Homework Equations Is it true that 0 \leq f(x)\leq 3 for 0<x<1 \int^x_0 tf(t)dt \leq x^2 for all x \in (0, 1)? "The Attempt at...

So I have the equation for Barometric law in terms of density as: \frac{\phi(z)}{\phi_{0}}=exp(-g.M.z/R.T) where R=Universal gas constant, z=height of sedimentation, T=Standard temperature, g=Gravitational acceleration, M=Molar mass. When this equation is used to calculate the height of the...

PLC Progamming -- How hard is it to learn? Hi everyone, I have an internship this summer and I'm hoping to convince them to let me independently study PLC progamming. How hard is it to pick up on your own? extra info: I've taking C sharp and C++ progamming classes in college Thanks!

From what I've experienced so far, classical mechanics (well, Newtonian since I'm still on K&K) is very difficult. It gets even harder because I have no teacher and my next math class is honors algebra 2 (I already know calculus though). I'm able to solve problems (I'm on chapter 3 about...

I can't wrap my head around this problem? I think that when you drill a whole like that, the cylinder will roll back to attain its equilibrium so need to hold it with a certain torque to keep it in place, but i do not know how to find the torque What i have in mind is: since T=dL/dt, but L=Iw(w...

I like using computations/modeling/simulation for many kinds of physical problems, whether it be for molecular dynamics simulations, CFD, DFT to determine the electronic structure and properties of materials, molecular dynamics, etc. I'm not interested in hands-on work as I hated my lab classes...

Does anyone here consider ecology a hard science?

I want to work in ecology and I think it has potential to be a harder science. I like hard sciences and I think sometimes ecology has the image of being a soft science. Does anyone know of the progress being made in ecology? Give me some advice perhaps? Thanks.

Hello everyone. I have a rather unusual issue in which I do not seem to some know/understand basic concepts in prealgebra, but do rather well in something like calculus. By basic concepts, I don't mean something like solving equations, but I don't understand why certain things work the way they...

I just started number theory, and I feel completely lost. I never did proofs in calc. I am used to watching the professor do examples, then with solutions manual at home see how the problems are done and use the manual if I get stuck. This book on NT has no homework problems or solutions. I just...

Suppose you apply to a grad school with interestes in nuclear physics experiment and then you are accepted, but you then change your mind to maybe cmt or hep theory. Would it be possible to change?

Homework Statement Given the following equation X(y) = y/(t*(sqrt(b^2+y^2)) - 1/p How would I go solving that equation X(y) = 0 with respect to y? The Attempt at a Solution I can choose a commen dominator called p*t*(b^2+y^2) But I when end up with ((y*p -...

Suvat equations -- car braking hard to avoid a collision Homework Statement A car (A) is speeding along a rural road, of width 4m with a speed of 25m/s when the driver sees another vehicle (B) of length 3.5m just starting to cross the road at a point 40m ahead. The drivers reaction time is...

We all know that hard materials scratch soft materials, and the effectiveness is related to the difference in their Moh's hardness level. My question is whether some minute amount of abrasion occurs on the harder material that is scratching the soft material? If so, is there any mathematical...

Hi Physics Forum! I want you guys to help me out. I want to learn physics the hard way. Let me explain. I'm currently finishing my sophomore year at Colorado School of Mines. I am majoring in Engineering Physics. I'm doing great in school. I've signed up for SPS and APS - Physics Today should...

Homework Statement A small explosive charge is placed in a rubber block resting on a smoother surface(frictionless). when the charge is detonated, the block breaks into three pieces. A 200g piece travels 1.4 m/s and 300g piece travels at 0.90m/s. The third piece flies off at a speed of...

Hello everybody, I have proved that: \displaystyle \lim_{n\to+\infty} n\int_{0}^1 x^ng(x)\mathrm{d}x=g(1) with g \in\mathcal{C}^0(\left[0,1\right],\mathbb{R}).But I don't know how to prove this: \displaystyle \int_0^1 x^n...

Homework Statement A rod of length L is attached to a ball of radius L/6 A spring is attached to a wall, and to the vertical rod 1/3 down the top (opposite the ball). THe rod is displaced a small theta, and released. Find period of oscillation. Homework Equations T = 2pi...

Hi. Tomorrow I am taking the ACS General Chem 1 exam as a final. It's supposed to be 40 questions but I heard it is incredibly difficult. I currently have a 95% in my class and need to get at least 24 out of 40 to get an A for the semester. The problem is that my class was so easy (we got to use...

Homework Statement let bk>0 be real numbers such that Ʃ bk diverges. Show that the series Ʃ bk/(1+bk) diverges as well. both series start at k=1Homework Equations From the Given statements, we know 1+bk>1 and 0<bk/(1+bk)<1 The Attempt at a Solution I've tried using comparison test but cannot...

Homework Statement 1. lim as n approaches infinity of ((n+1)^5-(n-1)^5)/n^4 2. lim as n to infinity (n!)^2/(2n)!Homework Equations The Attempt at a Solution 1.I split it up, got (((n+1)/n)^4)*(n+1)-(((n-1)/n)^4)*(n-1). I try to simplify that down to (n+1)-(n-1) and got 2 as my answer, since the...

1. Homework Statement You are coating a glass lens of index of refraction 1.6 with a film of material of index of refraction 1.7. You start with the thinnest film possible that creates a strong reflection for 610 nm light. You gradually increase the film thickness until you again get strong...

Would it be possible for biological life to evolve a part of itself to be as hard as iron? I’m thinking of a tree analog. The wood or bark can replace metal for a low-tech society. The planet itself is deficient in metals because of its history, so I’m not thinking that the life form uses...

Hello, First off, the theorem is "if f is continuous on [a,b] then f is bounded above on [a,b]. What is the name of this theorem? He doesn't say but I'm sure it has a popular name. Anyway, it's on page 115. Let me type what he wrote, then I'll say which part I don't understand...

Homework Statement I'm trying to determine the number of critical numbers for the function (3x-x^3)^(1/3). Homework Equations Critical numbers are where the derivative of the function is = 0 or does not exist. Critical numbers must also exist within the domain of the function. The...

Why is it difficult (counter intuitive) to imagine an entity (like an electron) that is a particle and a wave? I have seen in many texts/lectures that it is counter intuitive to imagine this sort of thing but I don't understand why. I have this image in my head that seems to make pretty good...

Neil Degrasse Tyson talks trash at premed students and doctors Just out of curiosity, are premeds really like that? How smart is the average premed compared to let's say a physics student or engineering student. Any thoughts? EDIT:I think someone posted this video before SORRY if...

HARD! Mathematic examination question Homework Statement $$\int_0^2\int_π/3^π (x^2*\sec^3 x^3 -12\ /\sqrt{e^π+x^2 +2x})\,dx\,d(theta)$$ :cool: Homework Equations I could not find any relevant questions on the web, however this is simply a question from an exam written the 14th of October...

Homework Statement In the equation for the bohr model of the atom, what is the n value for Li2+ ion? Homework Equations E = -2.178 x 10^-18J(z^2/n^2) The Attempt at a Solution Since it is Li2+ that means it has 1 electron. So z = 1. Now I have an equation with 2 variables...

While browsing through one of the AIP's relatively recent publications (written in 2012 concerning the classes of 2009/2010) I found some information I thought was out of line with the common conception that masters-only students are rarely if ever funded. According to the publication (see page...

I am working with a team of fellow engineering students to design and build a small (probably less than eight inches in all dimensions) robot. We have not yet decided whether to use wheels or continuous tracks, and I have spent some time today trying to understand the physics of treads. The...

Homework Statement How to integrate: Homework Equations The Attempt at a Solution I used formula: sin^2(t) = ( 1-cos^2(t)) and now it's: Then: u=cos(t) du=-sin(t) What to do next?

Homework Statement $$y''-2y'+5y={ e }^{ x }cos2x$$ Homework Equations The Attempt at a Solution I still haven't completed the question but I just want to know if I'm on the right track. It's becoming ridiculously tiring to just complete 1 question. Is it supposed to be this long?

Homework Statement I am having problems with the following problem: "For a noninteracting gas of N particles in a cubic box of volume V = L^3 where L is the length of the side of the box, find the solution, \rho (\mathbf{p}^{3N},\mathbf{q}^{3N},t) , of the Liouville equation at time t, where...

Why is it so tough to give a definition for something even if we know what it is? For e.g. Math:- There is no proper definition of math, many people argue about what exactly is it. But still, even if we do not have a proper definition, we know what math is and what it's not. When calculus was...

Well obviously I'm not talking about mentally challenged people, but if two people are relatively distant in pure IQ tests (given the same initial education on abstract concepts that may aid such a test), will it play any significant role after a point? Will the smarter person ever be able to...