Formulas Definition and 522 Threads

I'm having trouble figuring out this problem. I'm not sure what equations to use or how to start it, can anyone help?? 1. A ball is attached to a string (extentionless and massless, of course) of length L. The string is attached to a frictionless pivot point. When the string is vertical, the...

I would like some "simple" (yeah, right!) math formulas that I can create an EXCEL spreadsheet to calculate flight profiles for a sub-orbital space plane with a 2,000 to 12,000 mile range. Please note, my math skills are 45 years old. If, as I suspect it will, calculus is involved, I would need...

Are there any techniques for doing this, or is it mainly a intuition and check process?

Hello everyone, My boss has asked me to find if there is any correlation between various sample parameters in a water quality study. We took around 150 samples, and for each one measured around 50 parameters e.g. iron content, free residual chlorine, level of coliforms, pH, etc etc. I...

Basically, this thread is just about (basic) Astrophysical theory because the Math is quite simple. I am attaching a set of word problems and all I am asking for is to get feedback on whether or not I am correct or not about the formulas I am planning to use for each question. If I am wrong...

Homework Statement I'm being given problems regarding the center of mass of a uniformly dense object, and I am told by the textbook to use: \frac{1}{V}\int x dV I have no idea what to do with that. I'm pretty sure I won't be learning anything about multiple variable integrals for two...

In a dish we pour water.We boil it for some moments.Then we turn off the oven and the water gets colder.The boiling is interrupted.If we pour cold water outside the dish (in contact with it) the boiling starts again.WHY does the boiling start again??

This is the problem: Suppose A\in\mathbb{R}^{n\times k} is some matrix such that its vertical rows are linearly independent, and 1\leq k\leq n. I want to find a matrix B\in\mathbb{R}^{m\times n} such that n-k\leq m\leq n, its elements can nicely be computed from the A, and such that the...

I have been searching for formulas to determine the flow rate and velocity of air through an orifice at a given pressure differential. I need to know the flow rate to determine the CFM requirements of the compressor. And I need to determine the velocity to be able to accurately size the...

What do these hexagonal shapes in chemistry and biochemistry mean? I believe they are called "skeletal formulas" but how are they written, and how do they work? [PLAIN]http://www.beatingaddiction.com/img/addictions/l-4038-e593256abe47451acdc9e8be36e78c18.png Does each of the joints in these...

I'm slowly trying to understand sp relativity. I admit I got lost in the last thread I posted :blushing:. But thanks to all who replied! I have a question about the Lorentz transformations formulas. This is more of a mathematical question about how the formulas are derived. If you have...

bouyant force formulas ! Homework Statement mass per passengers = 65 kg ; density of seawater = 1 025 kg/m3 g= 9.8N/kg number of passengers=4000 Homework Equations calculate the bouyant force on the total cargo and passengersThe Attempt at a Solution

The half angle formulas used when you solve problems that are like the following I mean: Ok, they usually look something like (I may have left something out, but I am putting down the general kind of idea of how they look and work:) Something like, Find Cos A/2 if Sin A =-1/2 and SinA is in...

find the volume inclosed by z=0 x=y and y^2+z^2=x ?? i am having trouble drawing it i know i should look on th shadow of it on the x-y plane and integrate by it i can project on every plane i want to and build the integral appropriatly i jast can't imagine this shape if i can find...

I need assistance identifying the required formulae to choose materials in building a span. The actual application is a bed frame of all things - but it can only be end-supported (simple end support). The entire bed will move up and down on rails (this is in a motor home - which is why...

Homework Statement I need to know how the equation Dx= Vx\sqrt{}2(Dy)/a is valid.

I notice that sometimes there may be 2 ways of getting to the answer -- using energy, or "forces'. Can I always just use forces? (i.e. f=ma) instead of those energy formulas?

Homework Statement A simple model of the core of a tornado is a right circular cylinder that rotates about its axis. If a tornado has a core diameter of 200 feet and maximum wind speed of 240 mi/hr (or 352 ft/sec) at the perimeter of the core, approximate the number of revolutions the core...

Homework Statement I'm just wondering why we don't have to worry about the possibility of taking the square root of a negative number when dealing with the half angle formulas for sine and cosine. Thanks.

Homework Statement 1.) A compound containing only C, H, and O, is subjected to elemental analysis. Upon completion of the combustion, a .4266g sample of the compound produces .5518g of CO_2, and .2259g of H_2O. What is the empirical formula of the compound? 2.) Maleic Acid contains 41.4%...

Here is the problem. It consists of a. b. and c. As you can see I found A and B, but C is giving me trouble. My work is also attached. I am assuming that when the question says "with what speed do the supplies land in the latter case." that i am finding final velocity. and I have already...

http://img864.imageshack.us/img864/9467/tnua.jpg I see an angle without a trigonometric function (delta theta - at the left side equations). I've never seen it before in a formula, and am not sure how to use it. Can anyone tell me how? Do I just translate degrees to radians and just plug the...

Homework Statement t = tetha FInd sin 2t when cos t = 4/5 Homework Equations no idea The Attempt at a Solution no. . . . btw what should I do 1st? I don't understand this question

find the volume inclosed by z=0 x=y and y^2+z^2=x i am having trouble drawing it i know i should look on th shadow of it on the x-y plane and integrate by it

Hi guys, new user here, I couldn't figure out which subforum would be suited best for this, so the mods may feel free to move this post around. (edit: should have posted in the Math&Science Learning Materials subform... mods, can you move this please?) I just wanted to make you guys aware...

(or "circular motion" problem) Okay, our lecturer pretty much has thrown us into cold water here. My big problem is getting the right list of formulas. I'm not sure this is a homework problems since I'm stuck in preliminary stages. Homework Statement...

I'm currently reviewing calculus that I learned 10 years ago, because I will be resuming an electrical engineering program in the fall. I am simply having a heck of a time remembering all of the formulas. Basically, I'm having to look at the problem, look at the list of elementary...

Im going to be taking calculus soon and I am doing ok in my courses, the one thing i feel i need to work on is the ability to manipulate mathematical formulas (change a variable or 2 to find what i need) for instance this formula A=P(1+i)^n can be re arranged as P=A/(1+i)^n also...

Hi all, I know that Frenet–Serret formulas are: dT/ds=kN dN/ds=-kT+fB dB/ds=-fN and also that this formula effectively defines the curvature and torsion of a space curve (http://en.wikipedia.org/wiki/Frenet–Serret_formulas), but: 1) Where else one can find those equations? 2) Do you have...

I am new here, and I have heard you cn use some script language to post equations. Can somebody provide a link to that script language?

Can you please give me any physics related formula that appears in this format? \frac{x^2}{4} Its part of a really crazy proof I am trying to do. The variables are irrelevant. Anything that looks like this would be fine! Thanks!

In excel, using Open Calc but I assume they're the same. Is their a way to put variables value into summing formulas. I wanted to sum from A1 to an A cell which is numbered A1+F4. So if F4 = 100 I'd want to SUM(A1:A101) I tried SUM(A1:A(1+F4)) but it gives a number error

Apparently the solution to the formula for undamped force oscillation mx''+kx=F0*cos(ωt) is x(t)=C*cos(ω0*t-α)+[(F0/m)/(ω0^2-ω^2)]*cos(ωt) where C is a constant, but are there any websites that show that derivation in an easy-to-follow way? I've tried Googling both the formulas and the topic...

I am having a hard time figuring out the signs for some of these formulas: First of all, U=Potential Energy V=\frac{U}{q} \int F dr = \int Eq dr = - Work Since, Work=K=-U Therefore \int Eq dr=+U U=\frac{QqK}{r} Therefore, V=\frac{KQ}{r} BOTH U & V have a positive slope of 1/r...

So there's a circular helix parametrized by \vec x(t)=(a\cos(\alpha t), a\sin(\alpha t), bt) and you have the matrix K given in the Frenet-Serret formulas. In the book I'm reading it says that -\alpha^2 is the nonzero eigenvalue of K^2. Can someone explain how they know this is? I understand...

How would you simplify (2n+1)! Is the same as (2n-1)! ?

Hello, we have the following example: Assume that (y1,y2) are discrete valued and follow such a distribution that the pair are with probability 1/4 equal to any of the following cases: (0,1),(0,-1),(1,0),(-1,0) . E{y1^2*y2^2}=0 E{y1^2}*E{y2^2}=1/4 I don't understand how the...

Greetings everyone, As we all know, when learning new topics in physics, it is often necessary to learn derivations of abstract formulas. When I go over these derivations, I rarely have trouble understanding them. However, I was curious on people’s opinions as to what degree these derivations...

Hi folks, I am in the energy industry, and we do linear/multilinear regressions stats. One of the concepts being introduced to supplement standard way of doing regressions is make use of: (1) Coefficient of Variation Root Mean Squared Error (2) Net Mean Bias or Abs (Mean bias)...

I am going to make a R.C. airplane and need help understanding the physics behind it. I have found these formulas for lift and drag. Lift=Cl*(r*V^2)/2*A Cl=2*pi*AoA Drag=Cd*(r*V^2)/2*A Cd=Cd0+Cl^2/(pi*A*R*e) Now I have two questions. First, are these the correct formulas for finding...

Homework Statement 1. write Newton's law in terms of s'' theta and g for a pendulum 2. define s'' in terms of theta'' Homework Equations The Attempt at a Solution 1. G = -mgsin theta and G = m s'' but i can't get all three of the required variables into one formula...

Homework Statement For the following series, write formulas for the sequences an, Sn and Rn, and find the limits of the sequences as n-->infinity Homework Equations N/AThe Attempt at a Solution an is easy, = the limit of which does not exist. This is where I get stuck, I know Sn= But I don't...

Homework Statement Of the following, which correctly shows an ion pair and the ionic compound the two ions form? Homework Equations a. Fe3+, O3+ = Fe2O3 b. Cr3+, I- = CrI c. Cu2+, O2- = Cu2O2 d. Sn4+, N3- = Sn4N3 The Attempt at a Solution a. Fe3+, O3+ = Fe2O3...

Homework Statement Find simple formulas for 1+ cos(θ) + cos(2θ) + cos(3θ) + ... + cos(nθ) and sin(θ) + sin(2θ) + sin(3θ) + ... + sin(nθ) The Attempt at a Solution It's not really a homework question, but more for making a problem that I'm trying to solve a little bit more simple...

Hi. I know about the general formula for an ellipse: x^2/a^2 + y^2/b^2 = 1, that can be used to isolate y and calculate x,y points in excel. That's great, so far so good. That will create a ellipse, with horizontal A (x) axis and vertical B (y) axis. But what if one wants to rotate the...

Homework Statement I can make intuitive sense out of cofunction identities but the compound angle results completely blows my mind. Is there a way to make sense of them without having to think about the proof everytime? Or should I just memorize them Homework Equations The...

just revising for gcse's and there always seems to be a question with three unknown denominators and you have to rearrange the equation they are usually like 1/a+1/b=1/c make b the subject of the formula can you explain how to do this

I am looking for Physics books which that focuses on how the Physics formulas are derived. I know that some formulas were derived by experiments and how each of the controlled variables relate to each other. That is fine for me too as long as it has the experimental data; although i prefer it to...

2 Questions please hello. i need help to Understand how can i Write Empirical formula for Al or in general how to Write Empirical formula? 2)i also need help to Understand how can i know what Ion i will get from Ba and P ? i think for ba is will be Negative because there more...

Hi to everyone I'm new to this forum and if someone knows about formulas or how to generate the arithmetic and progression geometric and with the software Mathematica 5.0?! Both of these have starting member and step for calculation...Thanks in advance, G.S