Formula Definition and 1000 Threads

Hi This i suspect is a very silly question. I have a battery charger for rc helis. The charger is supplied with 24Vdc via a pair of computer power supplies. The PSU's are supplied with 240Vac from the wall. I am trying to size up a generator so i can charge at the field. The charger has two...

I'm making an AC generator with a stationary coil and rotating magnets. What would be the correct formula to find induced voltage at a certain rotation speed (along with the units)? All sources I've found are either non-applicable or do not explain what units to use. Thank you for the help.

hello folks, I am learning about how create a equation dimensional to formula Force (m*a). I know this formula written this way: [F]=[ma] where: m=mass a=acceleration -> L/T² The result is [F] = M * (L/T²) * L⁰ My result it's right? Why T, relative time, has exponent two in formula...

Sorry if this is more of a HW question (if so then moderator please move my question. Thanks!) Hi, I'm trying to get an expression for a best fit curve of the combination formula (##_nC_r##). As far as I can tell, the curve is a simple parabolic curve, and its shape doesn't change. It's just...

Homework Statement [/B] I just got this formula from class : Q=mc(T2-T1) and got task to make 2 more formulas from this oneHomework Equations How do I make these formulas : T1=? and T2=? The Attempt at a Solution T2=Q:mc-T1 T1=-T1 T1=Q:mc+T2 Thanks for help

Homework Statement Hello All via the following x, y values , a formula needs to be decided for the 'Y ' variable. Basicaly Consider the table below for x and y (are they directly proportional or are they inversely related ? ). and also to find out the corresponding formula. Pl. see the...

This is my first writing in forum. And I'm not good at English... Please understand my poor writing. Resistance force : F=kv2 (N) Base puissance : P (W) Time : t Fuel-efficiency : e (m/J) Economical Speed is fuel-efficient speed for a car. (e is maximum) Energy for resistance force must be...

Hi, I was hoping I could get some things cleared up. Recently my Solid State professor mentioned that we could simply, from the chemical formula, predict where the band crossings are going to be. For example, take LaFeAsO. Since La has a valency of +3, Fe of +3, As of -3, and O of -2, he...

I'm (a music academic) teaching a musical acoustics course to a very mixed group (music students, science students, and neither). Today, I covered the basic concept of simple harmonic motion and how this produces a sine wave pattern of motion over time. In the extra time we had left over, I...

ok so this is a bit of a boring question, so sorry in advance, but for some reason I am struggling with this. I am deriving the seesaw formula. Now I have gone through the derivivate and I get A : ## m_{\nu} = - m_D^T M^{-1} m_D ## Now I have seen other derivations where they get B ...

So I need to compare the results of the volume formula of a cylinder to the results of the integration. In geometry, you learn that the volume of a cylinder is given by V = πr2h, where r is the radius and h is the height of the cylinder. Use integration in cylindrical coordinates to confirm the...

Consider this equation: f(x(t),y(t))=2(x(t))^2+x(t)y(t)+y(t) One way to calculate df/dt is directly using the chain rule: \frac{df}{dt}=4x(t)\frac{dx}{dt}+\frac{dx}{dt}y(t)+\frac{dy}{dt}x(t)+\frac{dy}{dt} \frac{df}{dt}=(4x(t)+y(t))\frac{dx}{dt}+(x(t)+1)\frac{dy}{dt} Another way is by using...

Is there a way to reduce the math in my formula algebraically: BestCost = lowest+((((highest+lowest)/2)-lowest)*0.6667); I want to use BestCost to filter out any Cost that is higher than 2/3 of the low range of the average. I hope that makes sense. Thanks

Source: http://www.nbi.dk/~polesen/borel/node4.html#1 Differentiating this equation we get the second order differential eq. for fn, (1-x^2)f''_n-2(n-1)xf'_n+2nf_n=0 ....(22) But when I differentiate to 2nd order, I get this instead, (1-x^2)f''_n+2(n-1)xf'_n+2nf_n=0Applying General Leibniz...

What formulas do Diesel Electric Locomotive manufactures use when designing new Locomotives? Are there any good books on the subject? Locomotive meaning train engine. I want to understand freight engine designs not passenger. Thank you, Kevin

Homework Statement Hi sorry if the titel is wrong I want to know if i can write this ##a^2 + u^2 -2au= (a-u)^2 = (u-a)^2## I get different results when integrating ##x^{-\frac{3}{2}}## in the range ##(a-u)^2## to ##(a+u)^2##

Please take a look of the photo. In the middle part, it says For each I, by division and gets the following results. Please further explain to me how to get the result by division. The photo is attached. Attempt: 1. Using f(x)=α0(x-α1)(x-α2)...(x-αn) form. If it is divided by x-αi , there...

I'm trying to find a formula for the current flowing through a wire that is only undergoing corona discharge into air. The wire is connected to a charged sphere, which provides the voltage. So far, I've just found formulas for certain ionization coefficients and electric fields, but no current...

Hi guys and girls, I've been working on this problem for a little while now but I'm not really getting the result that I want. This is what I have: I have what is essentially a big pair of vice grips controlled by a hydraulic cylinder. The cylinder opens and closes both arms of the vice grips...

Homework Statement All of the lanthanide metals (La through Lu) react with HCL to form compounds having eithe the formula MCl2, MCl3, MCl4, (where M represents the metallic element). Each metal forms a single compound. A chemist has a 0.250g sample of a lanthanide metal, and she wishes to...

Ok, so I know the curl represents how much something rotates about an axis. Let's assume we have a vector field F = Fx + Fy + Fz, where x y and z are direction vectors. So the rotation about the Z axis is made possible by a change in the Y direction and a change in the X direction. But the...

Hello PF! I am trying to find out how the formula for the magnetic field of a dipole magnet is derived, so far I've delved into maxwell equations, but I am finding the math too complicated to read. My state's education system is very far behind, and I am not accustomed to characters and symbols...

Homework Statement The formula for calculating the area of a curve in a polar graph is $$\large \rm \frac{1}{2}\int r^2~ d\theta $$ and is adapted from $$\large \rm Area = \frac{1}{2}r^2\times \theta $$ But the formula to calculate the arc length is very different from $$\large \rm Length...

Homework Statement in this question , ( in second photo) i don't understand that why at eccentricity ratio = 1 , P/ A is 83kPA , why the vertical line is drawn at a point between 100 and 150 KL/r to find P/A ? Homework EquationsThe Attempt at a Solution Is it wrong ? Or I left out something...

1. Homework Statement See image. Homework Equations I thought that Fx=p*u1*A1(u1+u2)+(p1*a1)+(p2*a2) would be the correct formula however I cannot seem to get the stated answer of 1.8kN. The Attempt at a Solution Using the above formula, p1v1=p2v2 to find u2 and p1a1=p2a2 to find p2...

Homework Statement show that the general solution of the differential equation d^2/dt^2 + 2 *alpha * dr/dt + omega^2 * r = 0, where alpha and w are constant and R is a function of time "t" is R = e^(-alpha * t) * [ C1*sin( sqrt(omega^2 - alpha^2) * t) + C2*cos( sqrt(omega^2 - alpha^2) * t)...

How to calculate the start up torque in inch pounds to start a plastic tube of 1.90" OD x 1.50" Id that has a shaft and ball bearings on each end. The shaft will be supported on each end, and will not rotate. The tube is horizontal. It would be similar to putting a conveyor roller in a frame...

Good Morning / Afternoon, I'm looking at a question which has been given to me and I'm trying to find out what the answer / formula would be to it. The question is as follows: A student has been asked to move a box of mass 15 kg onto a shelf that is at a height 2 m above the ground level and...

Homework Statement On the right bottom side ,when the switch is closed the equation is given V(EG)=+V+V(FG) The photo is attached Homework Equations Concept The Attempt at a Solution What is the difference between the back emf in the inductor and the p.d across the inductor? I think the...

Homework Statement Hi, I am really struggling with this Campbell-Hausdorff formula. The question requires me to use it to prove ei/h omega.L (x , p) e-i/h omega.L = R(omega).(x, p) where L is the momentum operator, x and p are the position and momentum operator respectively and R(omega) is the...

Homework Statement i was told that Power = torque x (angular velocity) Homework EquationsThe Attempt at a Solution I found that power has unit of Nm/s, torque x (angular velocity) has unit of Nm(rad/s), is the formula given wrong?

I am reading Tristan Needham's book "Visual Complex Analysis" and am currently focussed on Chapter 1, Section II Euler's Formula ... in particular I am trying to follow Needham's heuristic argument in support of, or justifying, Euler's formula - Needham calls it 'the moving particle argument'...

Hi - I'm trying to figure out the specific steps in a math textbook. I'm trying to figure out how the textbook did its algebra here with a quadratic formula to find an inverse of a function: Sadly there's a step I'm supposed to know by now in the simplification algebra in there 3 steps...

A steel cable 3.00 cm 2 in cross-sectional area has a mass of 2.40 kg per meter of length. If 500 m of the cable is hung over a vertical cliff, how much does the cable stretch under its own weight? Take Y steel ϭ 2.00 ϫ 10 11 N/m 2 .Y=([L][/o]F)/(A*delta_L) My attempt of solution...

Homework Statement Homework Equations a) the one given b) det(A-λI) = 0 find λ values using A c)use λ values to find eigenvectors The Attempt at a Solution This wasn't explained well enough so I can understand it in class. So far, I made the matrix being multiplied to A have the following...

Homework Statement can someone explain how to turn the formula of curvature T'(t) / r'(t) into | r'(t) x r"(t) | / | (r't)^3 | ? Homework EquationsThe Attempt at a Solution my working is in 317.jpgT'(t) / r'(t) <blockquote class="imgur-embed-pub" lang="en" data-id="a/q3t1U"><a...

I like to do a little survey and ask all who are interested: $$\text{What is the formula you regard as the most beautiful of all?}$$ In order to avoid everybody answer the same, please don't post one of the following: ##E = m \cdot c^2## ##E^2 = m^2c^4 + p^2c^2## ##e^{i\pi} + 1 = 0##

Hi there- I'm a graphic artist and work on a lot of "Spiral" cans. A good examples would be a Pillsbury Crescent roll can (after you whack it on the counter and unroll it). Or, a frozen Concentrate orange juice can unrolled. Anyway, I've created formulas in Excel to setup the page size that the...

Homework Statement i'm having problem of understanding the formula of area of moment of uniformly distributed load and uniformly varying load... the shape of graph for moment of uniformly distributed load and uniformly varying load.are similar,right...

Homework Statement in the old thread , i was told that The formula for calculating the shear stress is a beam is ##τ = \frac{V ⋅ Q}{I ⋅ t}## τ - shear stress V - shear force Q - first moment of area above the location where the shear stress is calculated. I - second moment of area for the...

Guys...need a little help Given Internal fluid Pressure P (Not Pressure Drop) flow rate Q Length Assume all the required parameters like viscosity, fluid density, temperature of the fluid, surface roughness and all losses (both major and minor) etc... I need to find the internal diameter of...

Hello, I'm a mechanical engineering student and I'm working in traction control for Formula 1 cars. The traction control in the cars is simple, too simple: an engine cut is done when the engine is at a certain RPM and slip value. A matrix of four values of RPM and slip has to be provided to...

In this video: The professor at the end (at about 7:28), used the formula for scale factor and redshift as a(t) = 1/z, instead of the actual one a(t) = 1/1+z. And when we apply both of them, they give very different results. So, how could the professor use the first formula, which we were...

Homework Statement Part (b) Homework Equations Vieta's formula The Attempt at a Solution Part (a): I'm kinda stuck on part (b) - I tried multiplying the product of roots and got b^2 d^2, but I have no idea on dealing with the sum of roots.

The position vector of the center of mass of a triangle is ##\frac{1}{3}(\mathbf{a}+\mathbf{b}+\mathbf{c})##. Is the position vector of the center of mass of a planar four-sided figure ABCD ##\frac{1}{4}(\mathbf{a}+\mathbf{b}+\mathbf{c}+\mathbf{d})##? Does this generalise to n-sided figure...

I am in search for journal articles/papers regarding the use of chromoly (41xx) or HSS tubes in racing car chassis (space-frame) for a literature review. I wasn't able to find any papers up till now. Any help is greatly appreciated.

Hi, If I want my spacecraft to accelerate at a rate that produces 1 G for a set distance (half way to another solar system) then decelerate at the same rate for the second half of the trip, what formula would I use? I would like to calculate the peak speed of the ship and the time dilation...

I need help in calculating the magnetic field outside of an iron core solenoid at different distances. I have made an electromagnet by taking a 99.99% pure iron (5cm in length and 1 mm in radius) and wrapping wire over it. I have measured it's magnetic field at the end and cannot find an...

Hello! Let's consider again a system of atoms with only two permitted energy levels E_1 and E_2 > E_1. When electrons decay from E_2 level to E_1, they generate a photon of energy E_{21} = E_2 - E_1 = h \nu. The number of photons (per unit frequency, per unit volume) emitted by such a system in...

Homework Statement integral of cot^2 x / csc^8 x dx Homework Equations u = cot x du = csc^2 x du The Attempt at a Solution if I use reduction formula I could answer this but it's going to be very very LONG SOLUTION I just need some basic integral work.