Formula Definition and 1000 Threads

Homework Statement The question is says: Two vessels divided by a partition contain 1 mol of N2 and 2 mol of O2 gas. If the partition is removed and gases ate mixed isothermally, then find the change in entropy due to mixing assuming initial and final pressure are same . Homework Equations...

I've been studying em induction and in my book it was explained by considering a metal rod of length l moving through a magnetic field and cutting through the field lines at a constant speed. So in time dt it moves through ds and they showed e=BA/dt, where A = l x ds(the area that the rod...

Homework Statement Which formula could be correct for the speed v of ocean waves in terms of the density ρ of sea-water, the acceleration of free fall g, the depth h of the ocean and the wavelength λ? The possible answers listed are: 1. v = \sqrt{gλ} 2. v = \sqrt{g/h} 3. v = \sqrt{ρgh} 4.v =...

Hi all, I have a question concerning the derivative of the formula of the number of nuclei. I hope I've posted this in the right section, I'm new here :P. Anyway, in the question, the given values are: At a certain time t, there is an amount of radioactive Br-82. The activity A is 7.4*1014 Bq...

Homework Statement (a) What processes changes atomic number by 1? What are the favourable conditions? How do you tell a neutrino is involved? How can we use this to understand the mass of this particle? (b) Use semi empirical mass formula to explain why odd-odd isobars are unlikely, while...

Sorry to bring this question up again. @aridno provides a nice formula of the moment of inertia I about the centroid in https://www.physicsforums.com/threads/calculating-polygon-inertia.25293/ as: $$...

I'm really happy about every hint! Homework Statement There is a ball on hight h which is dropped on a table. With every Impact the ball loses velocity v by a factor a<1. I Need to Show the following: The time T after the ball stopps bouncing is: T = \frac{1+a}{1-a} (\frac{2h}{g})^\frac{1}{2}...

I am using the following formula to determine the lb load against the bottom of a load cell from tightening the bottom anchor bolt nut (which anchor bolt goes through the center of the load cell structure and anchors to a bottom base plate) to a certain torque force, plus adding a live static...

Derive an exact formula (solve the recurrence definition) for the following recursive sequence: $s_n = 2_{s_n-1} - s_{n-2}$ where $n \ge 2$, and $s_0 = 4$, $s_1 = 1$. So I saw someone solving this by making it a differential equation or something? How would you do that? should I do let...

The first moment divided by the total mass is the center of mass. Now I know that a moment is a combination of a physical quantity and distance. So what is the First moment made up of? I know that moment of inertia is made up of mass times the radius (distance) squared.

Okay so the name may be bigging it up however i found something in my maths class today that i don't think has previously been published or at least I've never been taught it, it makes converting reacuring decemals a lot quicker I know about the over 9 rule however acording to my maths teacher...

Here's the source:http://web.mit.edu/dvp/www/Work/8.06/dvp-8.06-paper.pdf Regarding page 5 of 14, I don't understand the multiple integrals thing. What is that supposed to mean? Ain't we supposed to sum up all the paths but why do they do the multiple integral thing? Also regarding page 4 of...

From Apostol's Calculus Volume I, "Area as a Set Function" 1. Homework Statement : Right triangular regions are measurable because they are constructed from the intersection of two rectangles. Prove that all triangular regions are measurable and have an area of the product of one-half, their...

Homework Statement Using semi empirical mass formula calculate which isotope of oxygen (##_8O##) decays into mirror nuclei. Is it ##\beta +## or ##\beta -##? Homework Equations $$W(A,Z)=w_0A-w_1A^{2/3}-w_2\frac{Z^2}{A^{1/3}}-w_3\frac{(A-2Z)^2}{A}-w_4A^{-3/4}\delta(A,Z)$$ where $$w_0=15.8MeV$$...

While teaching momentum, we use the formula p=mv. Every year it comes up as to why the letter p is used in the formula and not other letters or symbols. I have conducted on-line searches and I stumble across explanations that mention Newton and his Principia along with other possible...

I have a problem I am trying to solve but no example provided can clarify the steps. I find this to be the problem with math examples, they provide problems but utilize same numbers so people who are not as math savvy such as I cannot figure the steps out as easily as they are provided. Anyway...

Homework Statement Show that both sides of the Stoke's Theorem formula are valid for the function F= using the triangular surface on the y-z plane with corners at the origin, (0,2,0) and (0,0,2). Homework Equations Stokes Theorem equation( not sure how to write it out here) [/B] The Attempt...

Using R = ρL/A, I am trying to get this formula, which is the change in resistance due to change in length, area, and resistivity. ΔR = (∂R/∂L)ΔL + (∂R/∂A)ΔA + (∂R/∂ρ)Δρ I understand the above conceptually, but I am confused about why we are multiplying by terms ΔL, ΔA, and Δρ. Intuitively, I...

Hi all, I need help finding a formula to find the volume of a solid that has a fixed width and depth but 4 different heights. To see what I mean, please take a look at a sketch I drew below. Thanks.

When the learning combination formula the formula nCr is usually derived using a deck of cards. There are n=52 different card. If you choose r number of cards, each is different so you basically start with n!/(n-r)! , then because the order is unimportant multiply by 1/r!. This explanation is...

I tinker with single cylinder 4-stroke (kart) racing engines a good deal. Flywheel design for optimum weight has always amazed me. Does anyone have formulas for optimizing the design? It's more than just saying "x" pounds is best, because the actual shape of the flywheel, width and thickness of...

hi all.. how to make formula for problem below : The average math test scores of 36 students is 86. There are four students attend subsequent replications and obtain an average value of 80. Find the average value of all the students! can you make simple? zidan3311

[FONT=Arial]Hi there, Just wondering if anyone here can help me with a real life math problem I have on my hands right now! I am going to borrow \$48,000 from a bank as an unsecured personal loan for a 3 year period. I have to make minimum monthly payments of 1% of the outstanding loan...

Homework Statement Determine the input resistance using blackmans impedance formula. I know all the ressisor values, and transistor data. Homework Equations [/B] Blackmans impedance formula The Attempt at a Solution Our teacher has given us a example on how to find the open loop gain, but...

Hey guys, The following formula is provided on the wikipedia page for downforce, D=0.5(WS)*H*alpha*F*rho*V^2 Where: D is downforce in Newtons WS is wingspan in metres H is height in metres \alpha is angle of attack F is lift coefficient rho, ρ, is air density in kg/m³ V is velocity in m/s...

There are n birds which need to be put back in a cage. In a specific 10 minute period each bird will be put back at some random point in time. Find a formula for the probability that m animals from n are put back at the same time, where the 'same time' means in the same 1 second interval...

Hey, Could anyone explain why Ia/Ib=2.512^(Mb-Ma), Where "Ia" and "Ib" are intensities of star a and star b and "Mb" and "Ma" are the apparent magnitudes of star A and star B? I thought the formula would be Ia/Ib=(2.512)^(Ma-Mb) because Ia=2.512^Ma and Ib=2.512^Mb. Thank You

I'm a little confused as to how to figure out the pressure exerted on a material pressed between two solid "press plates" Let's say we have 2 .5" thick x 12" x 24" hardened steel plates. I have a 1" thick layer of cloth (say 50+ layers) of 8" x 18" (1ft^2). The fabric is placed between the...

In the winters, I run on an indoor track, and use a footpod to calculate my distances with my GPS watch. The facility has three lanes, inside #1 is 181.6 meters, middle lane #2 is 187.2 and outside #3 lane is 194.3 meters long. The track is more less rectangular shaped as opposed to a circle...

Hello Master. I would like to ask a question about MS Excel and one of it's functions; CONCATENATE. I'm trying to write a huge number of reactions in the Excel as the following form : 12C (α,p) 15N So, since I have tons of reactions to organize according to the alphabetic order and isotopes...

I have encountered the following formula a couple of times (always in a physics context, of course..) \int_{0}^\infty \frac{dt}{t}e^{-tx}=-\log x Formally one can "derive" this formula by noting that \log x=\int \frac{dx}{x}=\int dx \int_0^\infty dte^{-xt}=-\int_0^\infty \frac{dt}{t}e^{-xt} But...

How i want to combine 4 physical forces in the universe into one equation like michio kaku do . What should i do and what i need ? how i want to prove my theory ? if succesfull how i want to show to the world ? Sorry I'm newbie

Can someone point me to a good, rigorous proof of Euler's formula (e^(ix) = cos(x) + i*sin(x)), starting from the definitions of sin(x) and cos(x) using the triangle (sin(x) = Opposite / Hypotenuse, cos(x) = Adjacent / Hypotenuse) and the definition of e^x as either Bernoulli's number (from the...

Why does electric flux have 'cos θ' in its formula??

I need to use this formula for a physics prac (my dad an engineer told me it). F = Weight (normal) x friction coefficient x diatmer of axle)/diamter of wheel x4 cause the trailer has 4 wheels. Can anybody point me towards a source of info on it, in particular the derivation. I use it to...

Hey guys! So I'm self studying Daniel Schroeder's Intro to Thermal Physics and we're to use Stirlings Approximation to simplify the following (assume that BOTH q and N are large, but we don't have a relationship between q and N): \Omega \left( N,q\right) \approx \dfrac {\left( \dfrac {q+N}...

Lately, I have been trying really hard to understand the Newton Leibnitz Formula for evaluating Definite Integrals. It states that- If f(x) is continuous in [a,b] then \int_a^b f(x) dx = F(b) - F(a). But one thing that just doesn't make sense to me is that why should f(x) be continuous in...

I know that the reduced mass, μ, of an object is: \mu = \frac{1}{\frac{1}{m_1} + \frac{1}{m_2}} \mu = \frac{m_1 m_2}{ m_1 + m_2 } But is there a general formula (or a simplified expression) for finding the value of: \frac{1}{ \frac{1}{x_1} + \frac{1}{x_2} + ... + \frac{1}{x_n} } ? Thank you.

Hi, According to Newton, F= (GM¹M₂)/r² Einstein proved that light bends around massive bodies, due to gravity. (because space bends around these bodies) Mass of light = zero, but its being affected by gravity. So, is Newton's equation not universal?

variable pi formula Diameter (mm) = 0.0000003 : (pi of D - 3.1416 )^2 Pi of D is variable from 3.1416 to 3.1589...

When reviewing Electric field I had some confusion as to what the subscripts on [F][/0] and [q][/0] mean. Also what are we calculating here? I know its the electric field but what does this term mean?

hi guys. i have 2 questions, how do solve this problem with formula [shortcut] : please, see attachment file.. thanks for your helping.. susanto3311

hello expert.. how do make sum formula for this below problem (2 question) : please, see my attachment picture thanks in advance.. susanto3311

Homework Statement If the mass of a horizontal mass-spring oscillator undergoing SHM is 0.5kg and the force constant is 20N/cm, what is the maximum restoring force of the oscillator? And what is the maximum acceleration? (Time period is 6s and amplitude of oscillation is 12cm) Homework...

I believe that the formula Vout = Vin * R2/(R1+R2) is used to calculate how much voltage whatever is connected to Vout will be receiving. So if: Vin = 12V R1 = 10 ohms R2 = 5 ohms Then Vout should be getting 4 volts But if we then connect an appliance with a resistance of 2 ohms to Vout...

Homework Statement [/B] Propenoic acid is a reactive organic liquid used in the manufacture of plastics, coatings, and adhesives. An unlabeled container is thought to contain this acid. A 0.2033-g sample is combusted in an apparatus such as that shown below. The gain in mass of the H2O absorber...

About the formula deltaPE=-qE(deltaX) .. Whats the negative sign means ?

Okay have need of rebirth do dying brain cells (brain has gone to mush) If I wished to use and electromagnet to draw (F=force) on an object (M=mass) the distance of x/t What would I try to remember Or have I and just fergot the rules [ No I know it is forgot, but I'm retired now so it is fer...

Homework Statement The velocity of a particle is related to its position by: v2 = w2 (A2 - x2) where w and A are constants. Show that the acceleration is given by: a=-w2x[/B]Homework EquationsThe Attempt at a Solution a= v* dv/dt v=(A2w2-x2w2)1/2 dv/dt= 1/2 (A2w2-x2w2)-1/2 * -2xw2 v *...

Homework Statement My book says: "Let A and B be two events such that P(A) > 0. Denote by P(B|A) the probability of B given that A has occurred. Since A is known to have occurred, it becomes the new sample space replacing the original S. From this we are led to the definition P(B|A) ≡ P(A ∩...