Moment Definition and 1000 Threads

Hi, I was wondering why dipoles are singled out as a separate section in my physics textbook. For instance, after discussing electric fields the textbook specifies what a dipole is, dipole moment, and the electric field for a dipole. Finding the e-field for a dipole would be the same as finding...

Homework Statement Consider an electron with spin ##\vec{S}## and magnetic moment ##\vec{\mu}=-\frac{e}{m}\vec{S}##. It is moving with the velocity ##\vec{v}(t)## relative to the inertial frame of reference ##I## through the electric field ##\vec{E}##. Calculate the angular momentum the...

Hello, I was wondering if some one would be able to check my thought process on this. I have an object ( a boat) which I'm only able to calculate the tensors of the volume moment around its volume centroid. If i assume that the object has a uniform density ( which it does not, just bear with...

Homework Statement why there is no constraint of plate about a axis ? for moment about z -axis , i can have -2Bx +3By = 0 , where By and Bx = 0 which is shown in the top part of solution... Homework EquationsThe Attempt at a Solution

Homework Statement Mn+2 has a higher magnetic moment than Fe+2 but practically Fe+2 is ferromagnetic right? So more magnetic right? Homework Equations ## μ = √ (n(n+1))##[/B] The Attempt at a Solution For the Mn ion it comes to be √35 and for the ferrous ion √25 So yes Mn+2 is more...

Dipole moment is the measure of strength of electric dipole and is equal to product of either charge and distance between two charges. P=ql but as we know when charges are close the force b/w them is strong n when they are far away force decrease. But in above equation strength increases with...

Homework Statement Calculate resultant moment of forces about pt O and state its direction.Homework Equations Put the picture. Check it outThe Attempt at a Solution What I did was : About A : 60Nm B: 40 Nm C : 120Nm. I'm not sure to add or subtract for resultant. What I did:: Add. A-B as they...

Homework Statement A box shaped vessel, of ##4## compartments and ##80m## lenght, light displacement of ##800## tonnes loads ##200## tonnes in the first compartment and ##200## tonnes in the last compartment. Produce the shearing force diagram and bending moment curve. Homework Equations 3...

Homework Statement I need to know why my derivation does not work. I am attempting to derive I=2/5 mR^2Homework Equations I have seen people derive it using disks but my question is why do the shells not work? Where in my set up did I go wrong? Thanks The Attempt at a Solution I am attempting...

I just can't figure this out with the stresses and moments. What is the force required on the handle to get the 850N on top? Link to album: goo.gl/FYpc0k

in this video http://www.physicsgalaxy.com/lectures/1/44/234/Solved-Example-2#12(see only the question) the method illustrated is integration but i thought of an alternate method, moment of inertia of half disc with radius r2 is 1/2mr2^2 and that of half disc with radius r1 is 1/2mr1^2.so...

Homework Statement A solid sphere, radius ##R##,is centered at the origin. The "northern" hemisphere carries a uniform charge density ##\rho_0## and the "southern" hemisphere a uniform charge density ##-\rho_0##. Find the approximate field ##\mathbf E(r,\theta)## for points far from the sphere...

Homework Statement Theres an object which makes a pendulum motion.Lets suppose we hang the mass to the ceiling.We released the object with inital angle 0 to the ceiling.(I mean the angle between the object and the ceiling is zero).Whats the moment of the Inertia to the point A. A is a...

I'm having a hard time undertanding a concept of moment of inertia and Angular acceleration. Homework Statement We have a closed system above. M1 is a cylinder of 2 Kilograms, moment of inertia of a cylinder ( MR2 /2 ) with a string tightly rolled around it. This string connects to a free...

Homework Statement In our physics lab we were to set up a system looking like this: where the mass was released and the velocity/acceleration and of the ring was calculated using MotionLab software. Our goal was to find the predicted total moment of inertia by just calculating the moment of...

Homework Statement Find the moment of inertia of these composite objects. I've attached two different composite objects; each rod has length L and mass M. Homework Equations I = Icm + MD2 Long thin rod with rotation axis through centre: Icm = 1/12ML2 Long thin rod with rotation axis through...

Homework Statement Lets say i have a structure like this , at A and B are fixed support ( it resists moment about , force in x and y direction) I want to find the moment about the A , should I include the MA as well in my calculation or no ? Homework EquationsThe Attempt at a Solution moment...

Homework Statement Need to find the moment of inertia of a cylinder, about its center of mass, about the three principle axes. Z axis is normal to the circular faces of the cylinder. mass = M, radius = R, height = h Homework Equations ∑miri2 The Attempt at a Solution The Izz for whatever...

Homework Statement Find the moment of inertia for this composite object: M1=5kg at (3,4) and M2=3kg at (6,8) Homework Equations Moment if inertia for point particle = MR2 The Attempt at a Solution I'm not sure if moment of inertia should be componentized -- broken up into x and y...

This seems to be a crucial detail that I just glossed over, but when finding the inertia tensor of an object, is the origin always situated at the object centre of mass? For example: In the link (http://hepweb.ucsd.edu/ph110b/110b_notes/node26.html ), is it necessary to do the integral from...

Homework Statement The cubic is divided into 4 parts , A, B and C, D , each with thickness of 1mm , i am sked to find thesecond moment of inertia about x -axis Homework EquationsThe Attempt at a Solution i' m using the formula Ixx = Ix +A(d^2)[/B] for part CD, Ixx = 50(1^3) / 12 + 50...

Homework Statement In the image uploaded below, a boxed shaped object is shown. It is floating in water so the forces that act on it are buoyancy and gravity. The first and the last compartments are filled with evenly distributed weight. The middle 2 compartments are empty. Specifics are...

Homework Statement Question: In pairs figure skating, the heavy muscular male and the petite female skater skate towards each other and come to a stop when the female is lifted. Who undergoes a bigger momentum change? a. the heavier skater b. the lighter skater c. same momentum change d. we...

Homework Statement In the diagram, Disk 1 has a moment of inertia of 4.40 kg · m2 and is rotating in the counterclockwise direction with an angular speed of 7.50 rad/s about a frictionless rod passing through its center. A second disk rotating clockwise with an angular speed of 9.50 rad/s falls...

Homework Statement the homogenous plates shown in the figure has a mass of 10kg and is subjected to a forec and moments alonf its edges. If it is supported in the horizontal plate by means of a roller at A , a ball and a socket joint at B , and cord at C , determine the components of reaction...

Homework Statement What is the moment of inertia of the 4 kg disk below when it rotates about the center of mass? The mass of the disk without the holes is 6 kg . Homework Equations Center of mass equation: (1/M)(∫xdm) Moment of inertia of a disk: I = 0.5mr2 Parallel axis theorem: I = Io +...

Homework Statement The rods of length 2 meters and and mass 20 kg are joined at their ends to form a V shape. What is the total moment of inertia measured from the reference point perpendicular to the plane of the paper and at the point where the two rods are joined. (So find total moment of...

For a mathematics project I'm trying to figure out the moment of inertia for a propeller. I'm told that it is possible to find the moment of inertia of irregular objects through calculus, so I'm determined to figure it out using calculus. I plan on using a 3D modelling program (since I don't...

Homework Statement I need to find the final impact speed of the flame of a non-uniform candle. I am given that the mass per unit length increases linearly from top to bottom starting with 1kg/m at the bottom and 10kg/m at the top. I need to find how fast the candle flame is moving once the...

Homework Statement An object rolls down a ramp starting from rest, demonstrate symbolically the calculation needed to go from time given to a measured κ value here. Pick your favourite object and perform the calculation. d, m, R, t, h are known http://puu.sh/luare/10352d0479.png Soccer Ball...

1. The problem statementα, all variables and given/known data The moment of inertia of a Rod over an Axis XX' passing through the center of mass of the Rod at an angle α is- Homework Equations Moment of Inertia of Rod about the end, I =ML2/3 The Attempt at a Solution I=ML2/3 Answer of the...

Homework Statement If M[X(t)] = k (2 + 3e^t)^4 , what is the value of k Homework Equations M[X(t)] = integral ( e^tx * f(x) )dx if X is continuous The Attempt at a Solution I tried differentiating both sides to find f(x), but since it is a definite integral from negative infinity to infinity...

Homework Statement Got a spicy one for you today. There is a cylinder of mass 5kg (M) with no angular velocity and no velocity, on a surface of static friction constant μ=0.6 . It's radius is .1 meters (R). Its baricentric moment of inertia is characterized by I=.5MR^2 . Gravity is 10m/s...

Homework Statement This is the diagram, and the question is written there too (sorry for blurry picture) Homework Equations My main question is that when you draw out the FBD, at point A, there is a force going up, and a force going to the right. Why isn't there a moment around A? I have had...

If the moment generating function for the random variable X is M[X(t)] = 1/(1+t), what is the third moment of X about the point x = 2? The general formula only states how to find moments about x = 0. Thanks!

Homework Statement The great Sumatra earthquake of late 2004 had a main shock with an M_w magnitude of 9.1 and a large aftershock in early 2005 had an M_w of 8.6. Calculate the seismic moment, M_o (energy release) of each earthquake. Homework Equations M_w = 2/3*log(M_o)-6.0 Where log = log...

Homework Statement A uniform sphere and a particle are sent one-by-one with the same initial speed up the same incline. Each rises to a maximum height before falling back towards the starting point. The sphere rolls without slipping; the particle slides without friction. Use conservation of...

Homework Statement There is a string that is attached to a bar as shown below in the picture. What is the coefficient friction between the bar and floor before bar starts slipping. Reference...

Homework Statement That is the set up for experiment, and I attached the data I found in the lab. The lab given me the equation to find the moment of inertia of the cylinder Homework Equations Icyl = (2hgM_cylinder) * (1/(W_withcylinder)^2 - 1/(W_nocylinder)^2) The height is 0.9m The Attempt at...

Homework Statement To calculate the moment of inertia of a cantilevered tapered tube with mid-thickness large radius RL and mid-thickness small radius RS Homework Equations The Attempt at a Solution Area of the larger end of the tube AL=2*pi*RL*t Area of the smaller end of the tube...

mgfs can be used to find the moments of a random variable with relative ease. But you have to evaluate the function at t=0. Many times these functions are such that t can be all real numbers. How would you interpret an mgf evaluated at t=1. How does t relate to the probability distribution.

How do you know that if two random variables have the same moment generating function then they have the same probability distribution.

I'm confused about point 2. It says V=PQsintheta. How is that formula derived?

Homework Statement EDIT: DO NOT READ. I SOLVED IT.[/B] The collision in this problem acts at point C and acts a purely horizontal force in the inertial frame of reference. Homework Equations The Attempt at a Solution I understand the maths that is at work here, when we resolve the force...

Homework Statement I have 750+CD +200=200-Fay -Fby = 0 then can someone suggset at which point or axis i should calculate the moment ? seems like no point / axis is suitable to do that ... Homework EquationsThe Attempt at a Solution

Hey guys, So just completed a question on a sign post subject to wind loading of 2 kPa where you had to determine bending moments across x and z planes (picture below), to determine normal, shear, max stresses and then determine the factor of safety depending on the beam type you chose. That's...

I've drawn the free-body diagram of an airplane wing spar. I know the magnitude and location of all forces. What is the procedure to construct the bending moment diagram?

Homework Statement Is loosening and tightening of nuts using screwdriver considered as application of moment?? Homework EquationsThe Attempt at a Solution

Homework Statement i am asked to find the reaction at A and B ... Here's my working : 15(3/2) +15(5) +15(6)+5(6/2)=RA +RB moment about A = 15(3/2)(3x2/3) + (15)(5)(8) + (5x6/2)(8+4) + (15)(6)(14) -RB(14) = 0 so , i have my RB=148.9N , RA= 53.5N , which is wrong ? which part of my working is...

Homework Statement why the moment 560sin30 (0.25) isn't in clockwise direction ? the horizontal component of the 560N force is directed to the left , causing the moment in clockwise direction, am i right ? I have made my sketch beside in the diagram ... Homework EquationsThe Attempt at a Solution