Application Definition and 998 Threads

Suppose that the rate that people are getting infected in an outbreak of a virus is given by y=200xe^-0.5x. How many people in total will get infected from this outbreak? So i know I'm doing it right but i keep getting a strange number… so i set up an integral of that function from 0 to...

Homework Statement A spherical tank of radius 4(ft) is full of gasoline when a circular bottom hole with radius 1 in. is opened. How long will be required for all the gasoline to drain from the tank? Homework Equations dVolume/dTime = -a(2gy)^(1/2) The Attempt at a Solution Right...

I graduated with a Master's degree about a year and a half ago and am considering applying to PhD programs in Canada. During this period, I have been working in a field completely unrelated to my previous education and the PhD programs that I intend to apply. I have mainly been teaching to kids...

I want to find some application of the laplace equation on semi-infinite plate on physics where the PDE is looke like $$u_{xx}+u_{yy}=f , for a<x<\infty , c<y<d$$ $$u(a,y)=g(y), u(x,c)=f_{1}(x), u(x,d)=f_{2}(x)$$ $$\lim_{x->\infty} f(x)=\lim_{x->\infty} f_{1}(x)=\lim_{x->\infty}...

So I took quantum I using Griffith's and I only got an A- 3.7 out of 4. Will that look bad on my grad school application considering I'm competing with people who got A in quantum. I plan on getting into a PHD program and getting a Stipend. My overall GPA is like a 3.78.

I have a specific, for-learning-sake-only question on how the author of this link: http://www.math.ucla.edu/~yanovsky/Teaching/Math151A/hw5/Hw5_solutions.pdf gets past the details of the Intermediate Value Theorem on the following paragraph. If someone could fill in the details for me, it...

Here is the question: I have posted a link there to this thread so the OP can view my work.

The amount of time to finish a operation has an exponential distribution with mean 2 hours Find the probability that the time to finish the operation is greater than 2 hours. My thinking is to integrate the exponential probability function. After integrating it, I got -e^{-y/2} + 1 , 0 ≤ y...

Hi everyone. Just for a bit of background info, I earned my B.S. in Physics in May. I'm applying for grad school (for next year), but I'm kinda stuck on part of the application. It's kind of silly, but I'm a worrier. There's a spot on the application for you to select what degree you are...

Homework Statement . Let ##F## be the vector field defined by ##F(x,y,z)=(-y,yz^2,x^2z)## and ##S \subset \mathbb R^3## the surface defined as ##S=\{x^2+y^2+z^2=4, z\geq 0\}##, oriented according to the exterior normal vector. Calculate: ##\iint_S (\nabla\times F).dS##. The attempt at a...

Here are the questions: I have posted a link there to this topic so the OP can see my work.

Hi, I saw many templates for the cover letter of Ph.D. application. If I use them and do a little modification, is that OK or regard as a kind of plagiarization? Thank you very much in advance!

Homework Statement . Let ##(X,d)## be a complete metric space without isolated points and let ##D## be an enumerable dense subset of ##X##. Prove that ##D## is not a ##G_δ## (countable intersection of open sets). The attempt at a solution. Suppose that ##D## is a ##G_δ##. So ##D=\bigcap_{n...

Homework Statement A car is moving with speed 10m/s and acceleration 1 m/s^2 at the given instant. Using a second-degree Taylor polynomial, estimate how far the car moves in the next second. Homework Equations The Attempt at a Solution I don't get how you're supposed to apply...

Danish Postdoc Asks for "Diploma" in Application What Does That Mean? Hi all, I'm just trying to get a quick answer and I was hoping someone here might know. I'm looking to apply to a postdoc in denmark and it asks for the regular things (CV, cover letter, list of publications) but it...

Application on the limit definition of "e" Hi, I have known that: (i) (1+\frac{a}{n})^n=((1+\frac{a}{n})^\frac{n}{a})^a\to e^a (ii) (1-\frac{1}{n})^n=(\frac{n-1}{n})^n=(\frac{1}{\frac{n}{n-1}})^{(n-1)+1}=(\frac{1}{1+\frac{1}{n-1}})^{(n-1)}\cdot (\frac{1}{1+\frac{1}{n-1}}) \to \frac{1}{e}\cdot...

Hello everyone, I have a question about virtual corrections of an external fermion line. According to the LSZ reduction formula and what some other people say, we neglect the self energies of external legs and multiply the wavefunction therefor just with a squareroot of the wave function...

Hello I have applied to the University of Rochester and they require every student to submit the common application. the common application requires me to invite a teacher and a consular and this is not possible in my case and I have discussed this matter with UR consulars and one of them...

Homework Statement Show that the area of the plane bounded by the hyperbola (x)^1/2+(y)^1/2=(a)^1/2 and the axes of the coordinates is a^2/6 Homework Equations ∫yd x The Attempt at a Solution I just can't integrate the function (a)^1/2-(x)^1/2 considering the fact that there are x...

For those unaware, geometric algebra is a mathematical language that generalizes and simplifies a lot of the tools physicists work with (vectors, complex numbers, tensors, etc). I found a neat example in classical mechanics to illustrate its power. Simply, a charge in a constant magnetic field...

Greetings friendly physics folks, I could use some advice and/or general suggestions regarding a data visualization project I'm looking to get started on. If this looks like too much reading, please skip to the TL;DR below. The basic project components are: (1) A GUI of some kind...

In Heath's commentary on Euclid's Elements he stresses the importance of the application of areas (Book I Proposition 44) with, "The marvellous ingenuity of the solution is indeed worth of the 'godlike men of old'...". The proposition, "To a given straight line to apply, in a given...

need some help here. 1. find the volume (by washer method) of the solid generated by revolving the region bounded by $y=3+x^2$ and the line $y=4$ about the x-axis. 2. write the integral that will give the volume of the solid generated by revolving the region bounded by $y=e^{2x}$, $x=-1$ and...

Here is the question: I have posted a link there to this topic so the OP can see my work.

Homework Statement $$L\{ 1*{ t }^{ 3 }\}$$ Homework Equations $$L\{ \int _{ 0 }^{ t }{ f(\tau )d\tau } \} =\frac { L\{ f(t)\} }{ s }$$ The Attempt at a Solution $$L\{ 1*{ t }^{ 3 }\} \\ =L\{ \int _{ 0 }^{ t }{ { (t-\tau ) }^{ 3 }d\tau } \} \\ =\frac { L\{ { t }^{ 3 }\} }{ s } \\ =\frac...

Ok so I have a view ideas in mind for a project I was planning on doing involving genetic algorithms for my high school science fair class. I do have 3 mentors one a mathematician, a computer scientist who focuses on GAs, and a physicist who focuses on nano structures. here where I live, but...

Homework Statement How will you measure a voltage of range 0.0001 volts using the 741 OP-AMP? Homework Equations The Attempt at a Solution This a viva question and i couldn't answer. I don't know how to begin. Should i use Sample and Hold circuit or something else?

Simple question, are applications deadlines usually university-wide or does it vary from department to department (or college to college)? Or does the system depend on the whole university you're looking at? Thanks in advance.

Why are prime numbers important in real life? What practical use are prime numbers?

Homework Statement A 10.0 g piece of Styrofoam carries a net charge of -0.700 \muC and is suspended in equilibrium above the center of a large, horizontal sheet of plastic that has a uniform charge density on its surface. What is the charge per unit area on the plastic sheet? Homework...

1. Homework Statement . Let V be a vector space over the field R and S be a subspace of V. Now let f:S→R be a linear transformation. Prove that T can be extended to all the vector space V, i.e., there exists f':V→R such that f' restricted to S equals f. 3. The Attempt at a Solution . In...

I would like to apply to grad schools next Fall. If the school requires 3 recommendations, is it ever a good idea to include more? Also, what do you guys think about including a CV?

Homework Statement I have applied separation of variables to a transient radial heat equation problem. T is a function of r and t. I have reached the following step: Homework Equations T_2(t,r) = \sum_{m=1}^ \infty c_m...

Really need help for this one. Cheers! Homework Statement Question: calculate function z/(1-cos z) integrated in ac ounterclockwise circular contour given by |z-2pi|= 1 Homework Equations The Attempt at a Solution Clearly the pole in the given contour is 2pi. But the problem is: if it's a...

Here are the questions: I have posted a link there to this topic so the OP can see my work.

Homework Statement An object of mass 'm' if revolving in a circular path of radius 'R', this is analogous to a gravitational motion except that the force is applied from a point on the circle itself, it is required to find the force law Homework Equations from the point of application...

I have done quite a few introductory physics problems where calculus is involved .When refreshing the concept of work done by variable force,I find myself unsure about an application of calculus.The underlying concept which is puzzling me is at the very root of calculus .The work done by the...

Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :) Part B 1) A golfer hits a nice iron shot and the ball's height above the ground is given by h(t) = -16t^2 + 80t, where t is the time in seconds since the ball was...

Homework Statement Hi, there there is one question, which I find it to be solvable, but the answer is that it cannot be solved. Can someone explain me the answer given. I think there is a mistake on the underlined row, which leads to wrong answer. I am not sure, so if someone can help me I...

If you are having difficulty figuring out the percentage of an item and don't have a calculator, you may utilize this trick (which i still don't know how it came to be in my mind). Let: ##a## be a fractional number (percentage) and ##b## a whole number. If you make ##a## be a whole number...

Tom gave an honest assessment just now in another thread of the real situation with LQG which in effect includes the several roads from there to cosmology (eg. Agullo, Alesci, Barrau, Engle, Vidotto, Wilson-Ewing and others). He made a very good point which is that the problems are not...

So I'm in the Navy. I work on an aircraft carrier that just went into drydock. The drydock has a large trapezoid door keeping the water out on one side. Our captain wants to know how much force is being held back on that door. I found the dimensions of it and calculated it, but now I'm having...

I've been studying for a test and have stumbled upon another type of problem I'm not comfortable with yet. I need help applying the argument principle - the practice problems in my textbook all consider only polynomials in the first quadrant. In solving this type of problem I consider...

I've been studying for a test and have been powering through the recommended problems and have stumbled upon a problem I just can't seem to figure out. $$\int_{0}^{\infty} \frac{logx}{1+x^{2}} dx$$ (Complex Variables, 2nd edition by Stephen D. Fisher; Exercise 17, Section 2.6; pg. 167)...

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Hello, First, thank you for any assistance. I am a mechanic and my Super want's me to design a back-pressure system that will simulate field use of my machines in my shop. We spray several types of fireproofing thru hose's that vary in length between 50 and 500 feet. We use blower's that...

I would like to have a nice picture/simulation of the Earth - Apophis encounter on April 13th 2029. I found this applet http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=aPOPHIS;orb=1;cov=0;log=0;cad=0#orb but it seems to produce too great error for the time of encounter - the minimal distance much...

Hello, guys. My question is related to my research work and I really really need help. I am a Phd student involved to the work of one R&D department. We are currently working with a technology which allows us to improve the performance of Hall effect based current sensors, in particular we...

I apologize upfront, as I have no experience with math to begin with. However, I have a real life problem I am trying to figure out here at work and I would appreciate some help. Here is my situation: Homework Statement In a 3 dimensional plane, I have an artillery piece pointing at...

Homework Statement Let ##f:\mathbb{R}^3\to \mathbb{R}^3## such that ##v_1=(1,0,1) , v_2=(0,1,-1), v_3=(0,0,2)## and ##f(v_1)=(3,1,0), f(v_2)=(-1,0,2), f(v_3)=(0,2,0)## find ##M^{E,E}_f## where ##E=(e_1,e_2,e_3)## is the canonical basis. The Attempt at a Solution i see ##v_1=e_1+e_3##...