Moments Definition and 598 Threads

Hi all, Speed is a ratio of the distance traveled per unit time. But what then is work done and moments? For example, work done is force multiplied by the distance traveled in the direction of the force. But how would you explain the rationale of multiplying these two quantities? As...

if i take moments at point O, does it mean that LTcos(a) = (L/2) mg and hence T = 32? but answer is 16. what am i missing out here? thanks!

Hello, I have a small question about moments and bending moments. So, if I have a beam with a loading given by q (N/m) which is given as a function of x then what do these calculations get me? \int xq(x) dx \int (\int q(x) dx) dx The first integral gives me the moment about a point because I...

Homework Statement A 5m long uniform plank of mass 8kg is supported by two pillars at 0.5m and 3m from the left hand end. a 20kg child walks along the plank towards the right hand end. calculate 1. the position the child ia at when the plank begins to tip 2. the forces exerted by the...

Hi I would greatly appreciate help on this problem. Homework Statement Ok so here is the problem Homework Equations The Attempt at a Solution I first tried to work out the moments for the block on the ground with no angle to the ground. moments about a = .45(35000*g) -...

hi i have two questions :smile:, that i cannot solve by my own: does anybody know how to calculate the potential energy of two quadrupole moments that are separated by a distance r?( i looked for it in all my physics books, but i did not find anything at all) and: if you have two...

Homework Statement Homework Equations The Attempt at a Solution The problem I'm having is that I'm not sure how to work out the reaction forces because of the applied moment of 50kN.m. I know that the formulas are the sum of forces in a single direction equals 0 and the sum of...

hi i am looking for an equation that gives me the potential energy of 2 quadrupole moments and their mutual distance is assumed to be large. and they have no total charge or dipole moments. does such an equation exist?

Just totally confused which value to use to get the area moments of inertia with this question The ship was initially looks like this the mass of the ship is 5000 tonnes two heavy cargocontainers each of mass 73,370 Kg each assume that the ship has a rectangular waterline area, with length...

(2 dimensions.) Given 2 forces acting on an object (not modeled as particle), you can project their lines so that you can find a point of intersection - X. On this point of intersection exists no moment caused by the 2 forces since the line action makes 0 degrees with the forces. It follows that...

I'm stuck on this problem at the moment. The answer is 19.08 nm clockwise but i just don't see how it can be. Check this. 2.8x(0.8+5.5)= 17.64 nm If I use the 4.6 it ends up 4.6x(0.8+5.5) = 28.98 nm I don't get how it can be 19.08 clockwise when there is only one force going...

Hi. I was assigned this coursework by my lecturer. The problem is I have only been taught how to analyse a solid beam section and not a hollow section as is shown in the problem. What I would like to know is how to calculate the area. Usually I would do this by calculating Length x Breadth. I...

Homework Statement You have i.i.d. random variables X1,...,Xn ~ Normal (\Theta,c^2*\Theta^2), where "c" is a known positive constant (relative variability = std. dev(X)/E[X]) and \Theta is an unknown positive constant. Find the first four moments. E.g E[Xj] where j=1,2,3,4.Homework EquationsThe...

Bending moments Help! Hi guys, didnt really know how the layout of a bending moment diagram would fit under the standard template provided so i'll have a bash at explaining the problem. On my school course i have been doing bending moments/diagrams and shear force diagrams, but a few days...

Would anyone be able to explain how to calculate and use bending moments? I have been studying cantilevers and Euler's strut and I don't understand the following: Why for a cantilever the bending moment is positive, and for the Euler strut the bending moment is negative. As far as I can tell...

I posted this as a part of a thread on the classical physics forums, but the doubt wasn't resolved, so I thought this might be a more appropriate place... A fixed beam is considered equivalent to a Simply supported beam (SSB) with a point load at its mid point(and thus having reactions Ra*...

Homework Statement ive been trying to figure our this mechanics question and I am rather stuck but unfortunately i haven't had much experience with moments find the normal forces applied to the installed stud at points A and B [PLAIN]http://img851.imageshack.us/img851/1826/photoc.jpg...

I have the solution's manual for this particular problem, but I'm having hard time understanding the steps they've taken. I've attached pictures of the problem below. For the shear, are they using 1/2*x*(wx/L) because it is equal to the area of the force? And for the bending moment, where are...

So if I start with a multivariate distribution f(x,y), I can find the marginal distributions, the conditional probability distributions, all conditional moments, and by the law of iterated expectations, the moments of both X and Y. It seems to me that I should be able to relate the conditional...

Homework Statement A square plate with edge a cm and areal density kr g/cm^2, where r is the distance (in centimetres) from P to one of the diagnals of the square. Find the mass. The Attempt at a Solution I know my diagram is wrong, and I know what the correct one looks like. However, I...

Hi I have a question regarding Moments of forces When in equilibrium we have a lever hinged at B which is in between A which is 120' to B and C which is Flat .. A force is applied to A at 50'(P) and another force to C at 70'=100N So breaking down P into components you get P Sin 50 (perp to A)...

There seems to be a good source here: http://www.cs.cf.ac.uk/Dave/AI2/node194.html But my problem is understanding the summation. What I am trying to do is calculate ellipticites and orientation angles of images using their second order moments of inertia. My images are in matrix...

Homework Statement A triangular plate is attached to a wall by two pins A and B. It is loaded at point C by A force F Homework Equations Sum of Moments = 0 Sum of Forces = 0 The Attempt at a Solution Moments act around bottom of plate F*L1=L2*Fa+L3*Fb Vertical Forces...

http://homepage.ntlworld.com/russelliott/shifting-cofg-1.png A rigid weightless beam is supported on 3 springs, spaced as marked. The forces in the 3 springs are initially equal (at 10N). The position of the 30N balancing force F to keep the system in equilibrium is determined from taking...

Homework Statement Through pulley B, set upon structure ABC, a mass (m) of 2 tons is being lifted in constant velocity. The beam AB is horizontal. Calculate the reaction forces at the beams. Ignore friction at pulley. http://img225.imageshack.us/img225/4750/236shrinked.jpg...

Hi all, this is my first post, so forgive me if this is in the wrong forum. (I believe it does belong here) We are currently doing moments in physics and I have seen this in a few homework problems but can't seem to grasp it. For example, in one question, we are given a new axis AA that...

I can't seem to wrap my head around the signs of shears and moments when applied to beams. Consider a cantilever beam that goes from x = 0 to x = L (with positive deflection, or y(x), corresponding to a deflection upwards). The standard equations tell us that \text{Moment} = EI...

Homework Statement http://img262.imageshack.us/img262/4343/scan22.png The Attempt at a Solution For the first question my attempt was: [PLAIN][PLAIN]http://img255.imageshack.us/img255/2628/screenshot20110110at182.png But this is wrong. The correct answer for part a was...

Homework Statement part a) A block of mass m slides up an incline with an initial speed v0. The incline is on an angle, θ, and block stops sliding at height H. -If the incline is frictionless, determine the max height H to which the block will rise, in terms of given quantities and...

Homework Statement A molecule of water has a dipole moment of 6.1×10–30 C m. Calculate the difference in potential energy between when its dipole is parallel to an electric field of 2.0×105 V m–1 and when it is anti-parallel to the field. Homework Equations U=kq1q2/r V=U/q V=Ex...

Homework Statement A uniform board is hinged at A and supported by a vertical rope at P, 6.0m from A. A man of weight 700N stands at the end of the board at point B, which is 15.0m from hinge A. If weight of board is 50N,calculate the tension T in the rope.Homework Equations By principle of...

just started looking at area moments. question i am stuck on is below. use the area-moments to calculate the mid span deflection produced by the given loadings, showing clearly all steps in the method and calculation: support condition: simply supported span: 7.20m section: 406x140x39...

I understand the principle of moments and how it is applicable to first class levers: A stone, at 1 m from the fulcrum weights 300N I stand at 3 m from the fulcrum: Clockwise Moment = Anticlockwise Moment F x 3 = 300 x 1 Therefore, I have to exert 100N of force to lift the stone. To...

A 3 pin frame ABCDE is supported at A and E. it supports vertical loads of 60 kN at B 80 kN at c and 100 kN at D as well as a horizontal UDL of 50kNm along DE. Calculate the reaction forces. I have REV = 124 kN and RAV = 116 kN. REH = 115.3kN and RAH = 215.3 kN. Are these correct Next...

Consider 4 equal masses at the 4 corners of a square of side b. First I took one of the corners as the origin and found the principal moments of inertia to be Ixx=mb^2, Iyy=3mb^2, Izz=4mb^2 after solving the secular equation. Again, I found the principal moments of inertia but now with respect...

Homework Statement When I try finding the principal moments of inertia with respect to different origins for any arbitrary configuration(assuming that the inertia tensor is diagonalized), I end up getting different values. Intuitively, this is quite acceptable because the mass distribution is...

Homework Statement I have a question on finding the principal moments of inertia of a discrete set of mass points on a plane. If I choose one of the mass points as the origin, I always end up having a diagonal matrix for the inertia tensor for any configuration. Isn't that weird? I sense...

Suppose there is a horizontal beam with length 1. There is a pivot at distance \alpha from the left end of the beam. The beam is held in place, and n weights are placed on it. The positions of the weights (x1,..,xn) are independent and drawn uniformly from the interval [0, 1]. The beam...

Homework Statement Two identical, infinitely thin, homogeneously charged cylinders (length L) are placed in the xy plane and form an angle phi (so that they make a V shape). Calculate the angle phi, for which the dipole contribution to the electric field potential at (x0,0,0) is exactly...

1. A heavy uniform bar is in equilibrium in the arrrangement shown (I cannot upload the picture, but the bar is resting on a pivot with two weights at either end. 1.5m to the left of the pivot with 1000N weight at the end. 4.5m to the right of the pivot with a 100N weight at the end) Question...

Homework Statement This is not a specific homework question, but it is a coursework question. I am having trouble with determining the direction for the moment of a couple. I understand that with couples in general, there is a force negative and a force positive separated by some...

I'm currently studying Agri. Mech. Eng but I need some help on this, I know roughly what to do but it's where to start: 1. Design a skimming boom for a biomass slurry transfer tank which can have a reach of 7.5m. Tool must attach to a "quick hitch" plate - factory spec for the loader is...

Homework Statement 2. The attempt at a solution I'm working on #49 ONLY. I know the top line equation is f(x) = x but I need to find the g(x), so how can I find with the point is given (4,3). Please help!

My previous post has been removed due to some reasons. I would like to ask another question: if a uniform metre ruler with weight of 1.2N, suspended at its mid-point from a spring balance. No other force is added to the ruler. The reading on the spring balance is 1.2N. Am I right? If...

Homework Statement [PLAIN]http://img25.imageshack.us/img25/5139/physicsproblem.jpg If F1 = 110 lb and F2 = 300 lb, determine the magnitude and coordinate direction angles of the resultant couple moment. Homework Equations MR = \Sigmar x F, M = Fd The Attempt at a Solution...

Homework Statement A chiropractor applies a thrust to the spinous process of T6. The magnitude is 400 N and it is applied 90 degrees to the y-axis. While this occurs the superior disc applies a force to the T6 body of 615 N, 75 degrees to the x-axis. The inferior disc applies a force to...

Having trouble with this "Moments about the coordinate axes" problem! When a force F is applied to the handle of the valve shown, its moments about the x and z axes are, respectively, M_x= -77 lb ft and M_z= -81 lb ft. For d=27 in., determine the moment M_y of F about the y axis...

Hey guys I'm having trouble with this simple statics problem. http://img443.imageshack.us/img443/7218/37statics.png [PLAIN]http://img841.imageshack.us/img841/6734/372.png My set up. [PLAIN][PLAIN]http://img543.imageshack.us/img543/9349/ya1x.jpg I'm confused on where I'm...

Homework Statement a uniform rule has a mass of 90g and its centre of mass is at the 50cm mark. the ruler is suspended by a thread at the 70cm mark, balanced by a mass of weight W hanging from the 80cm mark. Calculate the moment of the weight of the ruler about the 70cm mark. What is the...

What are the forces and the moments of the hole puncher when a load is applied? The only idea here is a hole puncher is a second class lever.