Area Definition and 1000 Threads

Homework Statement Use areas to evaluate the integral f(x)=5x+√(25-x2) on the following intervals a) [-5,0] b) [-5,5] Homework Equations ∫f(x) + g(x) = ∫f(x) + ∫g(x) also Area of a circle = pi(r)2 The Attempt at a Solution [/B] My first several attempts have centered around evaluating the...

What effect (if any) would changing the surface area of electrodes in a lithium ion battery have? Would it allow for faster battery charging? Faster discharge rate? Thanks in advance

[Moderator's note: Spin-off from another thread.] I'm sorry, does black hole have surface area? Did you mean the sphere defined by Schwarzschild Radius?

Homework Statement This is a question me and my friend were wondering about. How can one calculate the magnetic field due to a current carrying loop at a point in the area enclosed by the loop. For example, at point P as shown in the attached figure. Homework Equations $$B =...

The question is to find the area of a disk, r ≤ 2a×cos(θ) as in the figure "example-just an illustration" I used two methods, each gave different wrong answers - integrate 2a×cos(θ) dθ dr - from θ=0 to θ=π/2 and from r=2a to r=2a×cos(θ) ; then I simply multiplied the answer by 2. - integrate...

Homework Statement In triangle ABC, ∠C=90∘. Let D, E, F be points on sides BC, AC, AB, respectively, so that quadrilateral CDFE is a rectangle. If [BDF]=7 and [AEF]=28, then find [ABC]. Homework Equations Area of a rectangle, and triangle. Also can cut up the rectangle into some triangles...

Dear all --- This question raises concerns already expressed in https://www.physicsforums.com/threads/the-bekenstein-bound.671770/ but in a more specific form --- so that, hopefully, a more specific answer may be given. With the Bekenstein-bound-saturated-by-BH argument, we have that a sphere...

Hello all, This is the situation: a pipe, shown in de drawing below, is lifted at a constant speed of 1m/min. The pipe is closed at the top and open at the bottom. For obvious reasons, a ventilation hole is required at the top. The intention is to lift a minimum amount of water, in other words...

Hey guys!, this is my final year aeronautical engineering project that me and my group are going to work on! we have this concept of producing a roll in an uav/RC aircraft by reducing the area of the wing on one side while keeping the other side area constant or increasing it(gradually) and...

$$ F = k{R}^{4} $$ The flux F is volume of blood per unit time. This is proportional to the 4th power of the radius R of the blood vessel. All I am given is 3% increase in radius will affect blood flow how. I am to find whether is decreases or increase blood flow and by what percent. $$...

Homework Statement Find the coordinates of the centroid of the uniform area. Homework Equations equations for centroid coordinates at the top of my paper. The Attempt at a Solution

Dear forum I am working with thermal radiation. This is the specific formula: P = σ ⋅ A ⋅ T4 P = emitted effect (W, J/s) σ = Stefan-Boltzmann constant (5,67 ⋅ 10-8) A = area of object (m2) T = temperature of object (K) How can I get to know the...

This technically isn't a coursework or homework problem: I have a uniform Joint density function for the lifetimes of two components, let's call them T1 and T2. They have a uniform joint density function, both are positive it follows, and the region is 0<t1<t2<L and L is some positive constant...

Homework Statement http://i.imgur.com/lzTN7If.png Excuse the bad drawing Point E lies on the side AC of the square ACBD. The segment EB is broken up into 4 equal parts as well as the segment ED. If JK = 3 find the area of the quadrilateral FGKJ[/B] Homework Equations Trapezoid equation to...

I was unable to fit any more details into the title. I'm a rising junior undergraduate electrical engineering student. My primary research interests (at the moment) are Electromagnetics, plasmas, solid state devices--pretty much any field with a heavy physics overlap. Unfortunately, none of the...

http://imgur.com/Q5gjaSG Consider the semicircle with radius 1, the diameter is AB. Let C be a point on the semicircle and D the projection of C onto AB. Maximize the area of the triangle BDC. What I'm thinking y=sqrt(r^2-x^2) From the formula of a circle x^2+y^2=r^2 A=1/2(x+1)y The area of...

Homework Statement I have a homework assignment that I find challengingA spherical baloon is being inflated at a rate of 10 cu.in/sec (i assume it's cubic inches per second) Find the rate of change of area when the baloon has radius=6Homework Equations So far I know that V=(4/3)*pi*r^3...

Homework Statement The parabola y = 6x - x^2 meets the x-axis at O and A. The tangent at O and A meet at T. Show that the curve divides the area of the triangle OAT into two parts in the ratio 2:1. Homework EquationsThe Attempt at a Solution Here is my working with my sketch. So I thought I...

Homework Statement A dielectric-filled parallel-plate capacitor has plate area A = 15.0 cm2 , plate separation d = 9.00 mm and dielectric constant k = 4.00. The capacitor is connected to a battery that creates a constant voltage V = 15.0 V . Throughout the problem, use ϵ0 = 8.85×10^−12 C2/N⋅m2...

I really like mathematics, physics, and programming/simulation/computer modeling. I want to try my hand at physics research. However, I don't want to build sensors or spend most of my time building experiments. I really like coding and data analysis. I am thinking that astrophysics research...

Homework Statement Determine the moment of inertia of the cross sectional area of the T beam with respect to the x' axis passing through the centroid of the cross section.(I'm attaching a diagram) Homework EquationsThe Attempt at a Solution Hi! I'm having a little trouble with this problem...

Find the area of the region in the first quadrant bounded by the line $y=x$, the line $x=2$, the curve $y=\frac{1}{x^2}$ $$\int_{1}^{2}\left(x-\frac{1}{{x}^{2}}\right) \,dx$$ just seeing if this is the way to go.

Hi, I am making a faraday cage to be used in reactive ion etching of silicon. I was wondering if the size of the cage, or the surface area has any impact on it's effectiveness or how it works? I know the size of the mesh and the material I use, as well as whether or not it is grounded all...

Homework Statement Flat space-time in polar coordinate is considered. The line element is ds2= -dt2+dr2+r2(dθ2+sin2θdΦ2) The actual answers are given below, but I can't come up to them. Need urgent help. Homework Equations dA = √g11g22 dx1 dx2 dV = √g11g22g33 dx1 dx2dx3 The Attempt at a...

My first question is, what is a diagonal metric? Secondly while calculating the area and volume of a diagonal metric, why do we calculate it like dA = √g11g22 dx1dx2 instead of dA = g1g2dx1dx2 ?

$a,b,c,d >0$, please prove we can construct an triangle with length: $\sqrt{b^2+c^2},\sqrt{a^2+c^2+d^2+2ac},\sqrt{a^2+b^2+d^2+2bd}$ and find the area of the triangle

In section 1.18 ("The area of an ordinate set expressed as an integral"), Apostol proves two theorems. the first, theorem 1.10, deals with the area of a function's ordinate set; the second, theorem 1.11, deals with the area of the graph of the function of theorem 1.10. (I have attached two...

Homework Statement I want to know if I got the answer correct and if my reasoning is sound. The text answers and solutions manual only gives answers/solutions for odd numbered problems. Here is the problem: And a direct link to the imgur page: http://i.imgur.com/Tko1xFh.png Homework...

we know that air pressure on our Earth is 1 atm. Also 1 atm = 10^5 P Also we know Pressure(P) equation = P = F/A So, F = P*A So if small area(A) in which we are standing is also taken then pressure force is that area(A) times 10^5(Atmospheric pressure in Pascal) i.e 10^5*A So why don't we...

I want knows if a formula for calculate the area of a quadrilateral non-cyclic needs of just four values (the values of the four edges) or if is necesseray 6 values (the values of the four edges MORE os values of the two diagonals)? This formula needs of 6 values (a,b,c,d,p,q): OBS: s =...

If the sun is at least 90million miles away and illuminates earth, and stars are the same as our sun, then am i correct in assuming that each star we see in the sky is illuminating an area of at least 90million miles!?? We see a little white dot from this far away but, does that little dot on...

Homework Statement A rectangular coil is composed of 150 turns of a filamentary conductor. Find the mutual inductance in free space between this coil and an infinite straight filament on the z axis if the four corners of the coil are located at Homework Equations B = (phi-hat) μoI/2πr dS =...

ZapperZ submitted a new PF Insights post Choosing a Research Area and an Advisor Continue reading the Original PF Insights Post.

I don't have a particular problem in mind here, so please move this thread if it's in the wrong section. I was wondering, when you're trying to find the area bounded between two curves, is there a foolproof way to choose which curve to be g(x) in (let S be the integral sign, haha)...

How to calculate some general area on a sphere for simplicity the unit sphere. Let's say I have a ball and I draw a ring on it. What is its area? I guess I need some initial point (some coordinate). Let's take a spherical coordinates with r=1. Element of area is \sin(\theta) d \theta d \phi ...

Find the area beween the curves $y=x^2$ and $x+y=2$ and the x axis First on graphing these the $x-axis$ seem irrelevant in that it is outside the area to find. y=x^2;y=-x+2

1- Let the linear operator on R^2 have the following matrix:A = 1 0 -1 3 What is the area of the figure that results from applying this transformation to the unit square? 2- I am abit confused here, I thought that the matrix for the unit square would be, 0 0 1 0 0 1 1 1... But...

What is the equation of the area of the trapezoid when a cylinder of radius R is cut by a plane inclined at an angle α? (Orange area of the figure) How can I relate it with Abase=π*R2 or with Ainside=2*R*L? Any hints please? Thank you very much in advance.

Homework Statement The problem consists of investigating the area between two functions of the forms (Parabolic segment): : y = mx + c and y = ax^2 + bx + c The investigation involves finding a combination that has one of each of the above functions and finding an area of one. The area...

1. Find the position of the centroid of the shaded area http://imgur.com/ieiSPPY 2. The black triangle with the square cut out is where the centroid must be located.I know that the object is symmetrical and the triangle can be divided into parts with two smaller right angled triangles I have...

Hello all, I'm a graduate Mechanical Engineer working for Atkins in their Water division. I now need to decide which sector to specialise in. I wish to choose areas that have a future and will grow and can be used in all sectors of Engineering.Here are my options: Pumping Systems Pipework...

Find the Area between the two functions. http://www4a.wolframalpha.com/Calculate/MSP/MSP16151chba72gif4040fg0000686h2hea7f943994?MSPStoreType=image/gif&s=54&w=381.&h=306.&cdf=Coordinates&cdf=Tooltips I know the bounds are from x=[-1,1] which gives me the equation... ∫ 2/(1+x4) - x2 dx I...

As the title says, I want to know which is the area of study of Biophysics. I am really interested in physics because of how interesting everything is. But also I have a great interest on subjects like neuroscience and genetics. Do you think biophysics would be good? Or better go with a biology...

Homework Statement Use the parametric equations of an ellipse, x = f(t)= a cos t and y = g(t) = b sin t, 0 <= t <= 2 pi, to find the area that it encloses.Homework Equations Integral for parametric equations. The Attempt at a Solution A = \int_0^{2 \pi} g(t) f^\prime(t) \; dt = \int_0^{2...

School sites seem like they don't paint the full picture of a program, so I'd love some inside advice: I am a transfer undergraduate and was wondering about: Boston University (accepted) Boston College (pending) Brandeis (" ") Northeastern (" ") Tufts(" ") My interests are in astronomy...

I have two images below. This is a single piston with pressure inside, the variables are as listed. P_in = 2700 Pa. P_out = 0 Pa. R1 = Radius 1 = 10 cm. R2 = Radius 2 = 5 mm. P_contact = ? My solution to P_contact is as follows. Area A1 of piston at R1 = .0314m^2 and area A2 at R2 =...

I may have misinterpreted this but today in calculus (AB) we were forming solids from 2 dimensional equations. One of the methods involved taking an integral of an area equation to solve for a solids volume. I got very excited as I often have difficulty remembering volume equations but am...

Member warned about posting without showing an effort 1. Homework Statement 'Using the graphing function on your Graphics Calculator, or otherwise, determine the radius for a minimum Surface Area.' I HAVE NO IDEA WHAT TO DO? Homework EquationsThe Attempt at a Solution

Homework Statement Find K at 4m, besides the F.s graph they also give me Kinitial = 2J Homework Equations W=F.d and W=Kf- Ki The Attempt at a Solution The first thing I did was to find the area under the graph. 1/2(4)(2)=4J W=F.d so that's my work. Then I replaced that 4J into the other eq...

Does integrating find the area between the curve and x-axis (regarless of it being a smile/frown or any other graph)? I've heard people say its the area UNDER a curve... but then how would you even get a definit answer surely it may be infinite if there's no restrictions? Thanks