Formula Definition and 1000 Threads

Hello, I found a derivation on NASA and several others that say something different. Can someone tell me which is correct? They differ by a factor of 3. This is confusing because some places say an object falling from 100m should deflect by 3cm but NASA says .16mm. Those are more different...

I really hope someone can help. I have spent the last week several hours a day trying to get this answer via Google. I am doing research on the practical difference between a mace and axe in combat. Strangely enough there's almost nothing concerning the techniques of using a mace in period...

Homework Statement v=2m/s m=10kg find the inertia At first i did 2m/s times by 10kg which is 20 but i also did 2m/s divided by 10kg =0.2 and 10kg divided by 2m/s= 5 but I'm unsure which method is correct. and momentum apparently isn't the same as inertia... Inertia is when an object carries...

I decided to review a little trigonometry. Why does tan(x + pi/2) = -cotx? I cannot use the tangent of a sum formula because tan(pi/2) does not exist. How about tan(x + pi/2) = [sin(x + pi/2)]/[cos(x + pi/2)] and then apply the addition rules for sine and cosine?

Is there a formula to calculate the radius that a rod of a given radius can be bent around while staying in the elastic range? For example, if I had a rod that was 1/4" in diameter and made of HDPE (which I think has a modulus of elasticity of 0.8 GPa), how would I calculate the minimum radius...

Is there a formula to calculate the radius that a rod of a given radius can be bent around while staying in the elastic range? For example, if I had a rod that was 1/4" in diameter and made of HDPE (which I think has a modulus of elasticity of 0.8 GPa), how would I calculate the minimum radius...

This is the time derivative to calculate the speed which a galaxy moves away from another galaxy. I don't understand how they get from da/dt (xi − x1) to (∙a)/a a(t). (xi − x1). Could anyone explain this? vi(t) = d/dt (ri(t) − r1(t)) = d/dt a(t)(xi − x1) = da/dt (xi − x1)...

Homework Statement Consider now a sample consisting of all possible n-digit integers where n is odd. Use your answers to the first two parts or otherwise to deduce a formula for the number of palindromic numbers within this sample.Your formula should be a function of n only. [6 marks] [Hint...

A 24 kg solid door is 220 cm tall, 95 cm wide. What is the door's moment of inertia for rotation about a vertical axis inside the door, 17 cm from one edge? I've looked at examples of how to do this problem. They connect it to center mass but I get confused when determining what the center mass...

Hello! I am a bit confused by the Doppler effect. Based on the formula it seems that if the source moves towards me with speed ##v## I hear a frequency ##\nu_1## but if I move towards the source with the same speed ##v## I hear a different frequency ##\nu_2##. However according to the...

Homework Statement I'm having trouble with solving a certain form of an equation with the quadratic formula. I think I'm making a dumb mistake somewhere with my algebra, but I can't seem to find it. Solve with quadratic formula: 1/x^2=4/(0.02-x)^2 Homework Equations 1/x^2=4/(0.02-x)^2 The...

hello i'm working on a project that consist on reading the light of LEDs on PCB to determine the color code (R,G,B) and light intensity but the sensor gives me values in LUX which is the illuminance and i need to convert them to Candela I found this formula in wikipedia but i didn't understand...

I was wondering whether or not there could be a "master formula" . What I mean by a master formula is, maybe not even a formula, some mathematical expression that would allow mathematicians to prove statements simply by plugging in some numbers into a formula. So I guess in a way a I am...

Homework Statement The fresnel-kirchhoff diffraction formula could explain diffraction,I think it should also produce the result with relatively small wavelength and large width slit in which case there is no diffraction. Homework Equations...

Homework Statement What is the dimension of ##M_{24}##? Homework Equations attached The Attempt at a Solution [/B] I am confused what the (mod 12) is referring to- is it referring to the ##[k/12]## where the square brackets denote an equivalent class and the ## k \equiv 2## / ##k \notequiv...

Homework Statement Hi, I am reading this book called, Introduction to Corporate Finance, by Berk, Demarzo, Harford (second edition). In it they try to explain how to calculate the number of periods in a loan payment formula. Authors give the following equation. $$ 0 =PV + PMT \times...

Hi, I am trying to write a function which would take two arguments: -> number of bits (which are a binary 0 or 1 value) N -> and acceptable number of mismatching bits M The function would statistically determine the probability of having M or less mismatching bits when randomly generating two N...

I'm trying to figure out how to calculate the Ascendant for a programming application but I have little experience with this level of math. My formula is this: 1998 December 31st 13:15 Brussels, Belgium. double d2R = M_PI / 180; double R2d = 180 / M_PI; double latitude = 50.8503*d2R; double...

I'm writing a real time 3D physics simulator that simulate bullet ballistics. Can I use the air drag formula that factors in drag coeficient and outputs drag force to calculate how deep a bullet will penetrate a target material? Say I substitute air pressure with target material density. And...

Homework Statement Calculate the integrals of the following functions on the given paths. Why does the choice of path change/not change each of the results? (c) f(z) = exp(z) / z(z − 3) https://www.physicsforums.com/file:///page1image10808 i. a circle of radius 4 centred at 0. ii. a circle...

Homework Statement I(λ, T) is 4 pieces multiplied: (8π/λ4) (hc/λ) (1/(ehc/λkT-1) (c/4). 1. Identify the meaning of each term. 2. Which term(s) fix the ultraviolet catastrophe? The Attempt at a Solution Well I know that the energy of a photon is given by (hc/λ), and I'm fairly certain it was...

In Young's double slit formula, the equation is d sin \theta = m \lambda Which means that sin \theta = m \lambda / d But, what if d < \lamda so the sine value becomes greater than 1? Will there be any interference?

We were asked to do an experiment where we had to prove the equation: T2=(4π2m)/Mgr Where M is the mass of the mass stack in kg (0.3kg), m is the mass of the rubber bung in kg (0.0226kg), T is the time taken for one rotation in seconds, r is the horizontal radius of rotation in meters, and g is...

Homework Statement Playing in the street, a child accidentally tosses a ball (mass m) with a speed of v=23 m/s toward the front of a car (mass M) that is moving directly toward him with a speed of V=20 m/s . Treat this collision as a 1-dimensional elastic collision. After the collision, the...

I am looking for a derivation of the following formula $$ \eta=\lim_{\omega\rightarrow0} \frac{1}{2\omega}\int dt dx\langle[T_{xy}(t,x),T_{xy}(0,0)]\rangle, $$ where $T_{xy}$ is a component of the stress-energy tensor. This is claimed in for instance https://arxiv.org/pdf/hep-th/0405231.pdf...

Homework Statement Show that ##a \sin x + b\cos x = c \sin (x + \theta)##, where ##c = \sqrt{a^2 + b^2}## and ## \displaystyle \theta = \arctan (\frac{b}{a})## Homework EquationsThe Attempt at a Solution We see that ##c \sin (x + \theta) = c \cos \theta (\sin x) + x \sin \theta (\cos x)##. So...

Homework Statement Homework Equations N/A The Attempt at a Solution I solved part a. I got an answer of 140. For part b, however, I am stuck. I came up with a set of points for D in the xy plane [(0,3)(0,6)(4,5)(4,8)] giving me a rhombus. How do i integrate this? I tried to split up the...

I've been reading my physics book and there they derived the formula ∑τ = Iα where τ is torque, I is moment of inertia of a rigid body and α is the angular acceleration. They did by taking an arbitrary particle on the rigid body with an applied external force tangent to the rotation. τ1 = Ftan *...

Moderator note: Thread moved from technical forum so formatting template is missing Hi, I have a block with a specified weight and a lever with a force at the other end. I was hoping someone could tell me what formula i need to work out the maximum length of lever before the block falls over.

Homework Statement Sodium chlorate(I) Sodium chlorate(V) Potassium nitride(III) Phosphorus(III) chloride Magnesium iodate(I) Homework Equations None The Attempt at a Solution I know the number in the bracket refers to what's before it, i.e. in sodium chlorate(V), the (V) means that the...

I am working on planetary orbits in an ellipse where the sun is at the foci, not the centre of the ellipse. I need a formula that describes the 'Change of Distance by Change of Theta angle' where Distance represents the distance between a planet to the sun (Planet is on parameter, Sun is at...

Hello,first time posting a thread not just here but generally so i'll try my best. So while i was in class we were learning about square roots,at first it seemed fairly easy,but when i asked my math teacher how do we find them more easily, he smiled and talled me:"The problem is,you just...

Hi all, I have doubts on the role of the Field Strength renormalization ##Z_\psi=1+\delta_\psi## when computing amplitudes. I never did this, maybe because it was not needed before, but i noticed that in the solution of a specific problem, to obtain the correct result, you need to multiply the...

It should be possible to calculate the output voltage in millivolts of a pickup coil at a given frequency, based on the number of turns of wire, the wire resistance / meter, the inductance of the coil in Henrys, coil capacitance, the BH max in Joule, or flux density in Tesla, and volume of the...

Homework Statement I don't understand the meaning of the formula... For the circled part in the first photo , what is the meaning of f(x1 ,x2 ) ? and also f(x0 , x1 ) ? Homework EquationsThe Attempt at a Solution I used the highlighted formula to find the second divided difference . But ...

For calculating a new "x" point of rotation I found the formula: x' = radius * cos(angle + -rotation) which converts to: x' = radius cos angle cos rotation - radius sin angle sin rotation Where does "radius sin angle sin rotation" come from? Jerry D.

Homework Statement Hi, Iv got to find the minimum diameter of a pipe if the pressure drops in a system is to be limited to 0.3bar. when delivered through a pipe of equivalent length 160m I have to use the formula Pressure Drop = 800lQ^2/Rd^5.31 I believe I have to transpose this to find...

Homework Statement 2. Homework Equations [/B] Consider a particle that is described by $$x(t)=(2.0-0.1t) \cos(0.5t)$$ and $$y(t)=(2.0-0.1t) \sin(0.5t)$$ t in seconds and x,y in meters. In previous subquestions we were asked to determine an expression for the module of the velocity vector and...

I am only aware that the formula has to do with entropy/thermodynamics. I could really use the help on how it applies in physics and what the formula is really about.

Homework Statement Using the Semi-empirical Mass Formula show that for fixed odd atomic mass number, A, the most stable isobar has a neutron to proton ratio given by N/Z = 1 + aCA2/3/(2aA) Homework Equations B(A,Z) = aV A − aS A2/3 − aCZ2A-1/3 − aA(Z − N)2/A + pairing term The Attempt at a...

Moderator Note: Thread moved from forum Atomic, Solid State, Comp. Physic, so no homework template shown. What function do they use Taylor's formula on? And can you show how they derive it? I know how one derives Taylor formula. Thanks! The text i taken from this...

< Mentor Note -- thread moved to HH from the New Member Introduction forum, so no HH Template is shown >[/color] Hi there, I found a thread from 2004 that perfectly answered my homework question here, but I don't understand how the person who responded came up with the answer. I would have...

I've been reading through a derivation of the LSZ reduction formula and I'm slightly confused about the arguments made about the assumptions: $$\langle\Omega\vert\phi(x)\vert\Omega\rangle =0\\ \langle\mathbf{k}\vert\phi(x)\vert\Omega\rangle =e^{ik\cdot x}$$ For both assumptions the author first...

Homework Statement $$ln(x^2)=4$$ Homework Equations ##a^{log_a(x)}=x## ##log_a(a^x)=x## The Attempt at a Solutionln(x^2)=4 <=> ##2ln(x)=ln(4)## <=> ##ln(x)= [ln(4)]/2## <=> ##log_e(x)= [ln(4)]/2## <=> ##e^{ln(4)/2}=x## <=> ##[e^{ln(4)}]^{1/2}## <=> ##sqrt(e^{ln(4)})##...

Homework Statement I am trying to wrap my head around what it means to find an explicit formula for the sequence of partial sums. Question: Find an explicit formula for the sequence of partial sums and determine if the series converges. a) sum from n=1 to n=infinity of 1/(n(n+1)) Homework...

Is this answer is proper? Propane is a natural component of natural gas and is removed during the refining process. Most gas appliances can be converted from one fuel to the other by changing the burners on a stove or changing or adjusting a gas regulator located inside the appliance according...

Homework Statement I need help when changing the formula of the yellow circled part to red-circled part ... Homework EquationsThe Attempt at a Solution I tried , but i didnt get what the author got ... Here's my working ... Which part of my working is wrong ?

Greetings, I am trying to learn more about Rayleigh scattering. I'd like to be able to calculate the amount of light scattered away from a beam as it travels through a volume of gas. So, I checked out the Wikipedia article: http://en.wikipedia.org/wiki/Raleigh_scattering I am not sure I...

Consider a system with a time-dependent Hamiltonian. We know that the evolution of the state of this system, is given by ## \displaystyle |\Psi(t_1)\rangle=T \exp\left( -i \int_{t_0}^{t_1} dt H(t) \right) |\Psi(t_0)\rangle ##. Do you think you can prove that the path integral formula for the...

Had to find the general formula for the gradient of a function r^n. r is the length of the vector connecting (x,y,z) with (x',y',z') I took the gradient of r^n and simplified it. If I plug in any number for in in r^n and go through the process, I will get the same result as if I take this...