Moment Definition and 1000 Threads

Homework Statement Suppose I have a rod with a know length, L, and 2 point-liked mass with know mass, m, each of them are fixed at both ends of the rod. And the rode has an axle connected at its midpoint where the axle is connect to a circular spring. The rod(with the 2 mass) is rotated 180...

I'm looking to find the resultant force of three forces and a moment: Fx, Fy, Fz, and Mx. I intend to graph multiple resultants. Would I just need to do the following to find the magnitude? Sqrt(((Fx+Mx)^2)+Fy^2+Fz^2) Thanks

hello, I am trying to find the new moment of inertia total for a rectangular stainless steel 4"x2"x.25"thk with a 3"x.75" flat bar welded on top of the short side of the rectangular tube. The short side (.75") of the flat bar will be welded to the center of the rectangular tube to the 2"...

Homework Statement Two children on opposite ends of a merry-go-round of radius 1.6 m throw baseballs at the same speed of 30 m/s but in opposite directions as shown. The mass of each baseball is 0.14 kg, and the moment of inertia of the merry-go-round and children combined is 180 kg-m^2. If...

Homework Statement A ladder weighing 200N is being held by a man. The man shoulder acts as a pivot. His arm is pushing an upward force F. http://i.imgur.com/dMrcRtK.jpg Where could a weight of 150N be hang upon, so that force F do not need to counteract the weight of the ladder...

I have a problem with the calculus of magnetic moment of Li-6. The configuration of protons is 1p_{3/2}, and the neutrons' one is the same. I have to add the magnetic moment of uncoupled proton and uncoupled neutron. I use the following formula for J=l+\frac{1}{2} (J is the particle...

Homework Statement Find the shear and bending moment diagram for a fully restrained beam with a length of 5m, a uniform distributed load of 1kN/m from x=0 to 2m, a point load of 1kN at 2m, and another uniform distributed load of .9kN/m from x=2, to x=5. Homework Equations The...

Why are clockwise moments taken as negative and anti-clockwise moment as positive? Why not the other way around?

The following equations are found in the following reference (Page 119): http://www.eeh.ee.ethz.ch/fileadmin/user_upload/eeh/studies/courses/power_system_dynamics_and_control/Documents/DynamicsPartI_lecture_notes_2012.pdf By definition, the inertia constant for a synchronous machine is...

Homework Statement A uniform cylinder 20 cm long, suspended by a steel wire attached to its mid-point so that its long axis is horizontal, is found to oscillate with a period of 2 seconds when the wire is twisted and released. When a small disc, of mass 10 g, is attached to each end the...

Homework Statement Three small spherical masses are located in a plane at the positions shown below. The masses are Q=0.700 kg, R=0.400 kg, and S=0.800 kg. Calculate the moment of inertia (of the 3 masses) with respect to an axis perpendicular to the xy plane and passing through x=0 and y=-3...

Hi, I'm looking for the Moment Coefficient (Cm) for a 3D Rotating Cylinder, this means, I there is a free stream of fluid and there is inmerse a cylinder rotating about its own axis , and also rotating about an axis parallel to the free stream. I found in the book of Peter Childs, called...

Homework Statement The Wikipedia article on spatial rigid body dynamics derives the equation of motion \boldsymbol\tau = [I]\boldsymbol\alpha + \boldsymbol\omega\times[I]\boldsymbol\omega from \sum_{i=1}^n \boldsymbol\Delta\mathbf{r}_i\times (m_i\mathbf{a}_i). But, there is another way to...

So, I've got a charge distribution given by: \begin{equation} \rho(r,\phi,z)=\frac{q}{2\pi R}\delta(r-R)\delta(z)\cos(2\phi) \end{equation} This, if I'm not mistaken, translates into a circular charge distribution located in the z-plane, a distance R from origo. Thus \begin{equation}...

In the bottom left, why does the BM diagram start at -4kNm rather than 4kNm? I understand that if you make a cut you yield this result but if you don't make a cut how would you know whether it starts at -4kNm or 4kNm? Thanks

Homework Statement The rotating parts of a motor have a moment of inertia of 15 kgm^2 and an optimum running speed of 1400 rev/min. When operating the motor is connected at optimum speed , by means of a clutch, to a shaft which has a counter rotation of 600 rev/min. The shaft has a mass of...

The rotating parts of a motor have a moment of inertia of 15 kgm^2 and an optimum running speed of 1400 rev/min. When operating the motor is connected at optimum speed , by means of a clutch, to a shaft which has a counter rotation of 600 rev/min. The shaft has a mass of 80 kg and a solid...

Homework Statement The thin, homogeneous bent rod has the mass m and the total length of 4b. It rotates with the angular speed of ω = ω0(24i + 12j - 6.0k) (only rotation) Determine the expression for the moment of inertia with consideration of the center of mass of the rod The figure...

[b]1. Homework Statement [b/] A timber beam, with rectangular cross section (h × b) is reinforced with additional full width (b) steel plates. There is a plate of thickness t securely connected on the bottom and a plate of thickness 2t on the top of the timber to ensure composite action in...

Show that the experimental data are consistent with a Lande g factor of 2 for each of the ions by calculating the saturation magnetic moment. Explain what this means for Cr. I've calculated J using Hunds rules and have the equation M = gμJn, where M is the saturation magnetic moment. BUT...

Can one adjust the properties of a sound wave to use it to spin an arbitrary object of shape S in a medium comprised of the same material. My intuition tells me that it would be much more difficult (if not impossible) to do this with spherical objects, so for now we can assume the object is...

Determine the resultant R and the point on the y-axis through which the line of action of the resultant of the loading system shown passes I have attached an image of the problem In my attempt to solve the problem I went about the following steps: 1- I chose my axis to be right in the middle...

Homework Statement A mass m is tied with a light string,which it's another end is winded at a axle fixed at wall,in which it's radius is r. Assume there is no friction.The mass is released from rest and falls a distance S after time t. Find the moment of inertia of the axle.(represents I in...

Homework Statement The Earth is slightly thicker around the equator and hence $I_{0}\neq I_{\zeta}$ I am curious in finding the angular velocity for the **precession** between using the fact that the distance between the spin axis and the precession axis is 10 meters on the surface of earth...

Homework Statement A homogenous disk with radius R and mass m lies in the xy plane so its center matches the origin O. Point O' is on the z axis at a distance s from point O. Axis y' passes through point O' at an angle \theta with the z axis. Find the moment of inertia around axis y'...

Find moment of inertia of a uniform quarter disc of radius R and mass M about an axis through its centre of mass and perpendicular to its plane ... I tried in the following way: I considered the relation. I= Icm + Md2 Where d is the distance between required axis and centre of...

Homework Statement To calculate I, the moment of inertia of an ellipse of mass m. The radius are a and b, according to the drawing. Homework Equations I=mr^2 Ellipse: \frac{x^2}{a^2}+\frac{y^2}{b^2}=1 \Rightarrow y=b\sqrt{1-\frac{x^2}{a^2}} Area of an ellipse: \piab The Attempt at a...

Draw the shear and moment diagrams for the beam in the figure. Clearly show all values, including the maximum shear and maximum moment and their positions on the diagrams. Assume the supports at A and C are rollers and D is a pin support. note there is a hinge at point B. I am having trouble...

So I have a question. I (moment of inertia) is basically mr^2 right? And r is supposed to be the distance from the axis of rotation. When the axis of rotation is directly through the center of mass, how is there Icm (moment of inertia about the center of mass). It's confusing to me, because so...

Homework Statement I need to derive the moment of inertia of a thin rod with its axis of rotation at the end of the rod. http://en.wikipedia.org/wiki/List_of_moments_of_inertia The third one. Homework Equations I = mr^2 The Attempt at a Solution I completely understand how the...

Twelve uniform, thin rods of mass and length are welded together to form a “wheel” as shown in the figure. What is the moment of inertia of this wheel for rotation around an axis through its center and perpendicular to the plane of the wheel? The welds contribute no mass to the wheel. I...

Homework Statement Homework Equations The Attempt at a Solution For part B, why is he using the formula for the moment of inertia about the y-axis? Why isn't he using the formula for the moment of inertia about the origin...

Hi. According to this page and other sources I found the z-component of the electronic magnetic moment is greater than the classically calculated value due to relativistic effects. Which makes me wonder: 1) What about the x and y components? I am completely lost as to why only the z axis...

Hi. I thought magnetic moment arose from closed loops of charge currents. How does then the angular momentum of the electron produce a magnetic moment? I mean, the electron is not a loop. Am I wrong in my initial assumption or am I understanding things too "classically"? Thanks.

Homework Statement Consider a cuboid of lengths a, b and c along the x, y and z axes respectively, centred at the origin. The task is to show that the moment of inertia of the cuboid of mass M and mass density ρ about an axis along the body diagonal, from (-a/2, -b/2, -c/2) to (a/2...

Hi I need some help explaining kinetic moment and moment of the center of mass. This is an example: http://session.masteringengineering.com/problemAsset/1529176/3/Hibbler.ch17.p107.jpg Okay I know that when you do moment equations: The Moment forces about some point is = to the kinetic...

Homework Statement For any flat object, located in the x-y plan applies to the equation: Ix+Iy=Iz where Ix,Iy,Iz is the moments of inertia about the x-axis, y-axis and z-axis. A flat circular coil has n windings and radius r. The mass of the coil is m. The coil is located in the x-y plan...

Homework Statement for the mass moment of inertia, why did they use Ix/Iy and not Iz? Homework Equations Ix=Iy= 1/12 m (3(r^2) + (h^2)) Iz= 1/2 m (r^2) The Attempt at a Solution

Homework Statement An energy storage system based on a flywheel (a rotating disk) can store a maximum of 4.4 MJ when the flywheel is rotating at 21,300 revolutions per minute. What is the moment of inertia of the flywheel? Homework Equations K= Ktranslational + Krotational Krot=...

Homework Statement Energy is released by the Crab Nebula at a rate of about 5×10^31W, about 105 times the rate at which the sun radiates energy. The Crab Nebula obtains its energy from the rotational kinetic energy of a rapidly spinning neutron star at its center. This object rotates once...

Hi, I am looking to use My/I to find the maximum bending stress for a beam My problem is I don't know how to find the bending moment- the reason why: The beam has more than one point of load, aside from the reaction points. (Pin joint cantilever beam) The sum of all moments equal 0...

P.W. Anderson in his essay "more is different" said that: "no stationary state of a system has an electric dipole moment". He used an example of NH3 to illustrate that. I then checked online and found that, Chemists said there is dipole moment in NH3 molecule, but (nuclear) physicists claim...

Homework Statement Homework Equations The Attempt at a Solution The problem is the integral is non-elementary, so now what? Part (b) follows trivially from part (a). But is there some kind of shortcut I have to take, because no matter what substitution I do, the integral...

How do I find the moment of inertia around the CoM of an object when the axis of rotation is not through the CoM? When Are summation formula used in equations and what exactly constitutes a point mass? regarding moments of inertia?

Homework Statement Hi all, I have a problem determining the moment and shear force at a location. The moment, I think, I have already solved. But I get stuck at calculating the shear force at the same location. It is for a element that is suspended in water, thus the weight of the element...

Homework Statement Find the magnetic moment of singly ionized helium in terms of Bohr Magneton I know the expression for the Bohr Magneton -- I am not trying to get a walk-through here as I want to do this myself, but I just want to know if I am correct in assuming that to get the problem...

Homework Statement I attached the question. Homework Equations M = r x F M = F x d Resolving forces, Fx/Fy/Fz = F cos/sin theta (depending on which angle you take) The Attempt at a Solution I can easily find the moment of the 100 N and 120 forces, but I'm having trouble finding...

Hi all, I just have a troublesome time wrapping my head around the concept of moment of inertia of a cylinder inside a cylinder. For example, in the attached figure The moment of inertia of the cylinder with radius 'r' around the point o, according to my understanding should be I_o = I_s+...

Homework Statement The Earth's magnetic dipole moment is 8.0 x 1022 A m2. (a) What is the magnetic field strength on the surface of the Earth at the Earth's north magnetic pole? You can assume that the current loop is deep inside the earth. 6.17e-5 T (b)How does this compare to 5.0 x...

Homework Statement Lets say you have some moment (given) at the end of a rod going clockwise. Do you have to factor this into the equations for forces? My professor has some notes written about it, but I don't know if he's incorrect.Homework Equations The Attempt at a Solution So if the moment...