Moment Definition and 1000 Threads

The question states: The calculation of the magnetic moment of a current loop leads to the line integral ∮ r x dr I am puzzled - shouldn't this be ∮ r x dl where r is the radius of the loop and dl is the small change along the loop? (I think dr would be in the same direction as r, so no cross...

Homework Statement Text description: Let V(z) be the potential of a ring of charge on the axis of symmetry at distance z from the center. Obtain the first two non-vanishing terms of the multipole expansion for V(z) with z>>a where a is the radius of the ring. Can you see by symmetry that the...

Homework Statement 2-1. A constant torque of 4 Nm is applied to an unloaded motor at rest at time t = 0. The motor reaches a speed of 1717 rpm in 4 s. Assuming the damping to be negligible, calculate the motor inertia in Nm·s2. Homework Equations T = J(eff) * dw/dt J = kg*M^2 The Attempt at a...

I have done some extensive self study on MOI but I don't understand it's meaning in application. An example is imagine a stick of butter is dropped on the ground. Now ignoring friction and the other variables we can remove for learning purposes, let's assume the butter stick is kicked and it...

Homework Statement There is a copy of the problem in the picture with the graph. Homework Equations M = F*d, M = Fxr, F_x = Fcos(theta), F_y = Fsin(theta) where theta is measured off the positive X axis, The Attempt at a Solution I tried splitting the force vector into X and Y components and...

Basically, I wonder what Chromoelectric dipole moment is and how it is formed...

I want to calculate moment of inertia of an angle L bent in form of a parabola. The parabola is attatcehd to a H section bent in form of a circle such that the center of circle and focus of parabola lie at the same point. I want to know how to calculate the moment of inertia for the whole assembly

I am trying to get more familiar with using calculus in unfamiliar situations, although I am stuck when thinking about moments. I am considering a wall that is depressed 0.7m into the ground and sticks out above ground by 2.0m (and has a width of w metres) and I am assuming that wind speed...

I am using VASP and it recommended to use the experimental magnetic moment for MAGMOM tag. The problem is I can't find a standard table of magnetic moments. I see different values from different sources. E.g In Web Elements, the magnetic moment of Fe is 0.096 μ/μN. But in another source, it is...

Hi all I need to find the relative stiffnes of certain I beams from here http://tsbluebook.steel-sci.org/EN/Browsers/Main.htm Im assuming all I need to do times the Youngs Modulus by the 2nd Moment of Area In my head I am making it more complicated than it should be so I hope this is all it...

The problem is to show that the moment of inertia of a rectangular plate of mass $m$ and sides $2a$ and $2b$ about the diagonal is $\displaystyle \frac{2}{3} \frac{m a^2 b^2}{a^2+b^2}.$ I did it using the traditional definition of moment of inertia, that is, $$I = \int r^2 \, dm.$$ However, the...

Hi everyone, I have a question which requires me to calculate aircraft pitching moment of inertia. I looked everywhere and can't find much about it, just the basis "what is inertia etc". Can anyone give an example on how to calculate pitching moment of inertia. Thanks a lot

Homework Statement Find the moment of inertia of a solid cone about its longitudinal axis (z-axis) The cone: x^2+y^2<=z^2, 0<=z<=h I_z = \int\int\int_T(x^2+y^2)dxdydzHomework Equations Representing the cone in cylindrical coords: x=zcos\theta y=zsin\theta z=z The Attempt at a Solution...

suppose a uniform rod of mass M and length L is at an angle B to the x axis, one end of the the rod touching the axis. wish to find moment of inertia about x axis. let the rod touches the axis at x=0. let D=density=M/L, and I will integrate along x axis, that means that at a distance x from the...

How is the polar moment of inertia in a rod calculated? Thanks.

i am trying to find the pure bending moment of this beam 1. Homework Statement simply supported solid beam 3m long W=100mm D=200mm with a UDL of 2tonnes/m and a point load in the centre of 200N Homework Equations is the pure bending moment at the peak of the bending moment diagram i have...

Homework Statement A forklift truck of weight W has dimensions shown in the figure below. Its centre of gravity G is mid-way between the front and the rear axles. When a uniform block of weight w (w < W) is placed on the front forks as shown, how the load on the rear axle will change...

On the website http://www.real-world-physics-problems.com/physics-of-billiards.html they take this equation ∑Mg = IG∝ where ∝ = -agx/r for the rotation of a rigid body where there is no slipping They then change the equation to F⋅(h-r) = IG(-agx/r) why is ∑MG = F⋅(h-r) when ∝= -agx/r?

Hi ,everyone… i wanted to clear my one confusion ,that what is actual difference between polar mass moment of inertia and simply moment of inertia…??

Could somebody take a stab at explaining how can quantum fluctuations give neutral elementary particles a magnetic moment? (in the usual explanation given by QFT textbooks, I think there are people around here denying the existence of quantum fluctuations, insert the more neutral expression...

Homework Statement For my IB higher level physics extended essay I will have to calculate the angular momentum of a cylinder rolling down a slope. The cylinder is made out of copper and will be filled with a known mass of car engine oil. I think i can obtain the angular velocity fairly easily...

Homework Statement Attached image Homework EquationsThe Attempt at a Solution The book says that the force P causes a torque about the x axis. Why is it not a moment about x? Why is it specifically a torque in this case?

Can someone explain how to determine if a compound has a dipole moment and how to determine how big or small it is (possibly numerical value)? I have a final tomorrow and I've looked this up on multiple website and cannot find any good explanation.

why there is a negative sign in the tensor moment of inertia??

Why the moment of inertia of a molecule about the bond axis is small enough to ignore ?

Homework Statement It has been suggested that we should use our power plants to generate energy in the off-hours (such as late at night) and store it for use during the day. One idea put forward is to store the energy in large flywheels. Suppose we want to build such a flywheel in the shape of...

Hi there, I am covering a topic on welding at university and I am struggling with deriving the second moment area for the structure attached. The desired second moment of area is also given in the attached image. The first part is particularly confusing to me as I know that the total second...

Hello everyone! New member here, as an ME major I always seem to come across very valuable information here, so I figured I would see if possibly someone here could help me. The problem I am dealing with involves modeling a car through certain motions such as hitting a speed bump, and part...

How do we know that moment of inertia cannot exceed MR2 for a solid body like solid cylinder, solid sphere, hollow sphere etc? R is the radius of the object in consideration. I know it has something to do with- that for solid bodies (in some cases hollow also) there are a lot of point masses in...

Homework Statement This isn't exactly a HW question, it's a question in my statics midterm today, he wants the reactions at the supports B and C, which is easy but the problem is this 60 N.m moment, all my friends were like :" let's just sum the moments around B ( due to the 50 N and the...

Why does hydroquinone possesses non zero dipole moment? The OH groups present at para positions on the benzene ring should cancel the effect of each other...if there is a plane change then exactly in which cases molecules do change planes?

Homework Statement A trapeze artist performs an aerial maneuver. While in a tucked position, as shown in Figure A, she rotates about her center of mass at a rate of 6.03 rad/s. Her moment of inertia about this axis is 16.1 kg·m2. A short time later the aerialist is in the straight position, as...

Hi everyone here is the question I'm having trouble with. included is my attempt and the question. 1. The Reactions at A (Assuming the boom weight is negligible) 2. The shear force and bending moment along the boom length and indicate the point of maximum bending moment. 3. The maimum bending...

Homework Statement A uniform, thin, solid door has height 2.2 m, width .87m and mass 23kg. Find the moment of inertia for rotation on its hinges. 2. Homework Equations I=∫x^2dm The Attempt at a Solution [/B]The way I set it up was that I made into strips of length H (height) and width dr...

Hii guys,i'm having problem in understanding momen. is it a effect of particular physical quantity at some distance like effect of force on some other point where it is not acting? N if it is,then why it shows effect of force 0 on where force is acting bcoz force have some effect on where it...

Homework Statement A puck of mass 82.0g and radius 4.09cm slides along an air table at a speed of v = 1.59m/s. It makes a glancing collision with a second puck of radius 6.97cm and mass 130g (initially at rest) such that their rims just touch. The pucks stick together and spin after the...

I'm working on a project involving analyzing the motion of a reciprocating saw. This saw converts rotational motion from an electric motor to linear motion by means of a slider crank mechanism. The power transmission goes from motor and attached driving gear, to crank, to connecting rod, to...

Homework Statement You place a magnetic compass on a horizontal surface, allow the needle to settle, and then give the compass a gentle wiggle to cause the needle to oscillate about its equilibrium position. The oscillation frequency is 0.321 Hz. Earth's magnetic field at the location of the...

Homework Statement Two particles, each of mass m, are attached one to each end of a diameter PQ of a uniform circular disk, of mass 4m, radius a with its centre at O. The system is free to rotate about a horizontal axis through A, a point on PQ such that OA = b as indicated in the diagram...

Homework Statement A barbell that consist of a long thin rod of mass M and length L is attached to two uniform spheres on each end. Both spheres have mass M and (1/3)L. The sphere on the left is hallow (spherical shell) and the sphere on the right is solid. What is the moment of inertia for...

Homework Statement The moment of inertia (I) of the bicycle wheel about the axle, can be obtained graphically using the equation: rm(g-a) = I(a/r)+Frictional Torque. Explain how to form two variables so that, I and Frictional Torque can be obtained from a linear graph. Identify the constants...

Homework Statement Calculate the moment of inertia for the system. The rods of length L are massless. Image here: http://imgur.com/O639ejf Homework Equations /answer[/B] I know that I=ΣMR^2 The correct answer to the problem is 32ml^2 I JUST WOULD LIKE TO SEE HOW THE PROBLEM IS DONE...

Homework Statement I am trying to calculate the dipole moment of a cylinder of volume charge density ##\rho_0## of radius ##R## and height ##H## with is center coinciding with the origin. My guess is that it should be 0 because of the symmetry but I am not able to show it. Below is my...

Homework Statement The first segment starts at -650 and ends at -1100. The second segment starts at 1200 and ends at 0. Homework Equations dM/dx = V The Attempt at a Solution I attempted to break the problem into two parts. For the first segment: Skipping a few steps: w = 100x dV/dx =...

Homework Statement Consider a square slab of magnetized material with sides ##2a##, and thickness ##d##, as shown. The magnetization is not uniform: $$M = M_o cos(\frac{2πx}{ a}) \hat{z} $$b) Calculate the total magnetic moment of this object. How would you guess the magnetic field decreases...

Is there a formula for the moment of inertia? A thin, uniform density rod is rotating about an axis that is off the end of the rod, so it looks a bit like this: ------- | (------- is the rod and | is the axis of rotation, so the rod is rotating out of the plane of your screen) I just have...

Homework Statement Disk with radius R σ = M/A I = ∫ mr2 Homework Equations Today we learned how to derive various moments of inertia via density equations (M/L, M/A, M/V). I understand all of them except on how to get MR2/2 for a disk. The Attempt at a Solution I = ∫mr2 σ = M/A dM =...

Two friends are carrying a 200kg crate up a flight of stairs. The crate is 1.25m long and 0.500m high and its center of gravity is at its center. The stairs make a 45 degree angle with respect to the floor. The crate is also at a 45 degree angle so the bottom side of crate is parallel to the...

Homework Statement A space station shaped like a giant wheel has a radius 95.0 m and a moment of inertia of 5.03✕ 108 kg · m2. A crew of 150 lives on the rim, and the station is rotating so that the crew experiences an apparent acceleration of 1g. When 100 people move to the center of the...

Hi, I am designing a beam to replace a load bearing wall. I have produced 2 separate UDL diagrams which, one for floor load and one for wall load. I am trying to find shear force and bending moment as in one for the total of the two diagrams. I know how to do it if the loads are spread...