Point Definition and 1000 Threads

Homework Statement Two point sources, S1 and S2, are vibrating in phase and produce waves with a wavelength of 2.5 m. The two waves overlap at a nodal point. Calculate the smallest corresponding difference in path length for this point. Homework EquationsThe Attempt at a Solution I really...

If I a pump with a main suction header and 4 smaller branch connections of difference sizes. Let's say for this example we have (2) 3", (1) 1", and (1) 2". Also let's say our pump is requiring 20 gal/min. The flow rate of each branch would be proportional to the area of the pipe correct? flow =...

Homework Statement For a system of discrete point particles the energy momentum takes the form T_{\mu \nu} = \sum_a \frac{p_\mu^{(a)}p_\nu^{(a)}}{p^{0(a)}} \delta^{(3)}(\vec{x}-\vec{x}^{(a)}), where the index a labels the different particles. Show that, for a dense collection of particles...

Homework Statement Calculate the gravitational force between a point mass and a circular platform. Homework Equations G=m1*m2/r^2 The Attempt at a Solution http://i.imgur.com/dfZf9GK.jpg The actual solution is different. They integrated by the angle between a/r (alpha) but i do not...

Homework Statement Hi, I'm working on understanding how a time independent point transformation . effects the Lagrangian and to see how what values are co and contra variant.Homework Equations Would these be correct formulations, or have I overlooked something? The Attempt at a Solution and...

What does it mean to treat something as a point mass. Give an example as well. Thank you.

Homework Statement Find all extrema and inflection points of the function ## y = \frac {x} {ln(x)} ## Homework Equations I did the first and second derivative by hand, and they worked out in CAS as well... ## y = \frac {x} {ln(x)} ## ## y' = \frac {lnx - 1} {(ln(x))^2} ## ## y'' = \frac {2...

THERE IS NO TEMPLATE BECAUSE GHIS HOMEWORK WAS PLACED IN AN INCORRECT FORUM Equimolar benzene and and toluene form essentially ideal solutions. At 20degC the vapour of benzene and toluene are 9.866kPa and 2.933kPa respectively. The solution is boiled by reducing the external pressure below the...

Hi, i'm looking for an explanation to this answer of a past paper that I'm doing, it's from OCR (A level) G485, question 1 b ii) the question on top, and answer on bottom i don't understand why would the point experience a negative electric field strength when it's getting closer to a...

Hi, I am trying to understand how light momentum transfers between point charges. I have a few questions if you could help me find some answers or direct me to some sources. Situation #1 Electron/Wire - There is an electron at rest light years away from a wire that has AC flowing thru it...

Homework Statement [ For a system of discrete point particles the energy momentum takes the form T_{\mu \nu} = \sum_a \frac{p_\mu^{(a)}p_\nu^{(a)}}{p^{0(a)}} \delta^{(3)}(\vec{x}-\vec{x}^{(a)}), where the index a labels the different particles. Show that, for a dense collection of particles...

Homework Statement Give the location and orders of the branch points at, and classify the singularities f(z) =\frac{1}{z^{1/2}} Mod note: Fixed LaTeX in exponent above and below. To OP: To write a fractional exponent such as ##z^{1/2}## use braces around the exponent, like this: ##z^{1/2}##. It...

I have a question on finding the inertia of a rod with a pivot point somewhere along it's length. So the inertia of a rod is IStick cm = 1/12 *m*L2 Does L2 = (2L/3)2 = 4L2/9 -> 1/12 *m*[4L2/9] or is it something like m*L2/12 + m* (2L/3)2? If it's the second one then may I ask why it's that...

Homework Statement Hi everybody! I have a crazy problem about Lagrangian on which I've been working on for two days without being able to figure it out. I have a solution, but I think there is a flaw in it. First here is the problem: A line rotates with constant angle velocity ##\omega##...

Homework Statement A +1.0 μC charge is placed at point X. A +4.0 μC charge is placed at point Y, 50 cm from X. How far from X, on the line XY, is the point where the electric field strength is zero? Homework Equations E = Q/4πε0r2 The Attempt at a Solution I know that the electric field is...

Homework Statement http://s32.postimg.org/4urcaq0xx/image.png The incidence angle of a light ray over a tile of glass with dy faces parallel is pi/3 rad. Find the distance between the incidence point and the refraction one of the ray with the tile, if the distance between these rays is 0.7 cm...

I'm doing an experiment regarding Nickel's time for a Curie point. The nickel will be connected to a wire on a pendulum and will be attracted to a neodymium magnet, but it will not be touching it. A candle will be placed in front of the magnet so that when the nickel moves toward the magnet as...

In acid base titration, we try to neutralize the analyte by adding sufficient titrant and observing the color change in the indicator. But if the analyte is neutralized, then it must always be at ph 7. Why is it that we use indicator of different ranges to check equivalence point?

1. Prove that nine point centre is the mid point of orthocentre and circumcentre.Homework Equations3. I know about euler line and its proof that centeroid,circumcentre and orthocentre are collinear and centeroid divides orthocentre and circumcentre in the ratio 2:1

Homework Statement Griffiths 4.15: A thick spherical shell of inner radius a and outer radius b is made up of dielectric material with a frozen in polarization. P = k / r in the r-hat direction. There is no free charge (why?). Find the electric field inside and out. Homework EquationsThe...

So was thinking a little bit about the ideal gas law. ##P V = n R T## And I read an article about the real gas law where they just edited few properties. ##(P + \frac{n^2 a}{v^2}) (V - nb) = n R T ## Where a and b are constant determined experimentally. So going back to our original point, Why...

Homework Statement Homework Equations E = kq/r2 V = -∫ E ⋅ ds W = -Vq The Attempt at a Solution a) I just summed up the electric fields: +ek/a2 +ek/a2 -ek/a2 so I get +ek/a2 as a result. Not sure if this is correct since -e has a y component so I was thinking to use sin but not sure which...

I have drawn a diagram of the incident and reflected rays of an object by the concave mirror. Red color shows the incident rays, black color shows the normals drawn from the center of curvature, while green color shows the reflected rays. Shouldn't all the reflected rays meet at one point. Any...

Hey all I have one last question for you. I just need clarification on point estimate and margin of error as I have to find both in a problem. Let's say the endpoints are 5.9 and 8.1. When I do a margin of error problem, I subtract the mean of 7 from 8.1 right? When I do point estimate do I add...

Hi guys, I was wondering if it is possible to have a pure planar rotation of a rectangular-prism shaped rigid body on a planar surface when it is subjected to a planar point force at the tip. Is there any range for the point force such that it can not break the static friction force (so no...

In a complex resistive mesh (grid), 2 points are chosen for applying a voltage source. Now there are many paths the current can take from A to B. And there is an equivalent resistance computed as well. But how to calculate the least resistive path? I.e. The path along which when traversed, the...

Homework Statement pivot point located at the middle of ramp( Point C). F1=250 lbs @ 12 in from point A F2=250 lbs @ 84 in from point A L=192 in angle from the ground is 25 degrees Homework Equations sum of moments equal to 0 sum of forces equal to to 0 The Attempt at a Solution I did sum...

The universe is expanding and at some point faster than light so once it reaches that point we won't see the light from those stars. I forget what this point is called. If someone happened to be watching a star as it crossed that point would we see it simply blink out or close to that or would...

Homework Statement A person is standing on tiptoe, with the total weight supported by the force on the toe. A mechanical model for the situation is shown, where T is the force in the Achilles tendon and R is the force on the foot due to the tibia. Find the value of T. Assume the total weight is...

On calculating the electrostatic potential at a point due to charge q, by definition, it is the work done to bring a unit positive charge from infinity to that point. Trying to find it mathematically, it should be ∞→R ∫E.dr...

I'm confused about this rolling without (or better with) slipping situation. Suppose to have a disk with initial velocity ##v## and angular velocity ##\omega##. The motion is to the right but the angular velocity is counterclockwise. There are no forces acting on the disk besides the kinetic...

Homework Statement A thin insulating rod with charge density lambda=+5nC/m is arranged inside a thin conducting cylindrical shell of radius r =3 cm. The rod and the shell are on the same axis, and infinite in length. What is electric field at point p? 6cm from the central axis. Homework...

Hi Community, I have this following tutorial question and I am stuck. I understand how to take the derivative and find the tangent line at certain value for $$x$$ Which would say if $$x=2$$ and the derivative of $$\frac{1}{x}$$ equals $$\frac{-1}{x^{2}}$$ then the slope would be...

Homework Statement Calculate the magnitude of the magnetic field at a point 100cm from a long, thin conductor carrying a current of 1A. Homework Equations B = ui/2pi(a) The Attempt at a Solution My question is why is this modeled after a problem with an infinite wire? When I first read it I...

Homework Statement Which one of these had the highest boiling point? A. 3-Pentanone B. 1-Butanol C. Butanal Homework EquationsThe Attempt at a Solution The answer should be 3-pentanone because 1- it's molecular weight is approx 76 compared to the other which has approx 64 2 - because of the...

Homework Statement a.) Let f(x)=(sin x)/x, x≠0. Define f(0) such that f is continuous at x=0. b.) Prove that if x0 is critical point of function f (f(0) defined as in part a), then |f(x0)|=1/(1+x02)-½ (Hint: use the basic properties of sine and cosine with given information.)The Attempt at a...

Homework Statement Two particles each with a charge of +3.00 μC are located on the x axis, with one particle at x = -0.80 m, and the other particle at x = +0.80 m. a) Determine the electric potential on the y-axis at the point y = 0.60 m.b) What is the change in electric potential energy...

What is an example of a rigid body rotating when one point is fixed and there are no net applied torques? And the fixed point is not the center of mass. I considered a cone rolling without slipping on a flat plane is such an example; the apex is the fixed point, but is there a net applied...

An accelerated charge emits radiation and so must lose energy. This implies that it feels a "reaction force" in the direction opposite the motion. Since EM interactions conserve energy/momentum, it must be possible to describe the reaction force in terms of EM fields acting on the charge. These...

Homework Statement So we have a horizontal bar. Distance = r Forces = F All numbers remain constant with the exception of the distance, denoted as r(set)() Length of bar = 1m F1 = 10N r1-1 = 0m r2-1 = .25m (behind the point of rotation) F2 = 5N r1-2 = 0.5m...

Homework Statement Find the local max, min, and saddle point for the function: f(x,y) = 2x^2+3xy+4y^2-5x+2yHomework EquationsThe Attempt at a Solution I've taken the two partial derivatives Fx = 4x + 3y - 5 Fy = 3x + 8y + 2 I know that the critical points will sit where both of theses partial...

Homework Statement Point with mass is moving along the positive direction of x axis, its velocity is described by (A-Bx^2)^(1/2). Show that its equation of motion describes dynamic harmonic oscillation and find period (T) of this oscillation. Homework Equations v=(A-Bx^2)^(1/2) A and B is...

At the very basic level, I understand this notion of discontinuity. But I am looking to understand this better, at a deeper level. Because I know I will need to know this well as I start to explore piece-wise functions. Why do we bother drawing graphs? I want to be able to tell if a function...

I understand that the derivative of a function ##f## at a point ##x=x_{0}## is defined as the limit $$f'(x_{0})=\lim_{\Delta x\rightarrow 0}\frac{f(x_{0}+\Delta x)-f(x_{0})}{\Delta x}$$ where ##\Delta x## is a small change in the argument ##x## as we "move" from ##x=x_{0}## to a neighbouring...

Conventionally we have the following equation of a plane ax+by+cz=d where d = ax0+by0+cz0. Where (x0,y0,z0) is a known point on the plane. Now if we try to find the distance between a point P and a plane we take any point on the plane Q (x,y,z) and find the vector from Q to P and project on...

As the name of the thread says, I am wondering what would the amount and the direction of the electric field at some point in the uniformly charged ball of radius R(it has a constant charge volume density) be at the distance r from the centre of the ball. Does anyone know what would they be? I...

Homework Statement In a wire passes the current I=21A. A part of the wire is bent to form three consecutive sides of a square with sides 40 cm. Find the induction of the magnetic field in the point O which is the center of the square. Homework Equations B=I*μ0*/2*pi*d The Attempt at a Solution...

If moving inside the event horizon of a super-massive black hole and theoretically surviving we could see the universe pass by at millions of years per second relative to someone on earth, where could we go where time passes at a much faster rate than someone on earth? For example where 2...

Homework Statement ≈ What is a 3D representation of voltage using Kq/r assuming a positive point charge and what is the equation in cartesian and cylindrical form2. Relavent equations Kq/r 3. Attempt at solution[/B] I was trying to get a better understanding of Voltage, to really FEEL...

Homework Statement A magnifier has a magnification of 9× How far from the lens should an object be held so that its image is seen at the near-point distance of 25 cm? Assume that your eye is immediately behind the lens. Express your answer to two significant figures and include the...