Moments Definition and 598 Threads

Homework Statement problem attached Homework Equations The Attempt at a Solution i had no problem with part i and ii , iii on the other hand, i simply don't know what i should do , i figured out that the required h will be the one making the center of mass of the whole body on...

Hi Guys, It has been a while since my last post but it's great to be back. I am having some trouble with part b) of this question. Don't fully understand the concept and what I'm meant to do. Any guidance or assistance would be greatly appreciated. Thanks in advance you legends!

Homework Statement Figure 5 below shows an approximation of the system of forces acting on the human forearm. The weight of the forearm is 25N and acts 15cm from the elbow of a girl lifting a dumbbell of weight 50N Find the 1)Force, F, exerted on the human forearm by the muscle in the...

Homework Statement (See pic attachment)Homework Equations Moment/Torque = Force * d (Force arm)The Attempt at a Solution I have so far Mx = Fz * ya My = Fx * za Mz = -Fx * ya How I got these answers is by looking at the cube from the component's axis and whether or not it produces a torque...

Homework Statement I have attached the diagram. The question says "Compute the Moment Mo of the 1.2kN force about the axis O-O. Homework Equations M = r x F AB = OB - OA Resolving forces, Fx = F cos Θ.. Fy = F sin Θ etc. The Attempt at a Solution Here are the axes I've made...

Hi. For whatever reason I'm really struggling with figuring out the direction of a moment in two dimensional statics problems. How can I tell if it's CW or CCW? The right hand rule just confuses me even more and I cannot find any explanation that breaks it down simply enough for me to...

Hello friends, I have this problem I've been stuck on for a while: Here are a few relevant equations: Moment = FxDy + FyDx Fx = F cos θ Fy = F sin θ etc. I can't even get past part (a). Resolving the 100 lb force is easy. It would be 100 sin 60 for the vertical component and - 100 cos 60...

Homework Statement The Attempt at a Solution I'm having trouble understanding how r1 = -1.5j and r2= r3 = 0. Can anyone make this a little clearer for me? I've spent quite a while trying to wrap my head around it but to no avail.

This isn't a homework problem - I'm just confused by something in a textbook that I'm reading (not for a class, either). I'd appreciate an intuitive clarification, or a link to a good explanation (can't seem to find anything useful on Google or in my textbook). My book states that one of the...

Some background: I am self studying dynamics and I have encountered a fundamental problem with either my understanding of linear algebra, or I am just plain dumb. So, I print screened the page of the book we're on. Now let me try to reduce some ambiguity in my question, I have a general...

i do not know why. does the magnetic moment of an atom come only from the spins of the electrons?

Homework Statement a rod of mass M and length L is supported by a smooth horizontal floor and leans against a smooth vertical wall, the mass density increases linearly with p=kr where r is the distance from the wall and k is a positive constant. a.finf the moment of inertia of the rod with...

This has botherd me for quite sometime ...imagine a beam or a simple scale supported at its centre and carrying equal weights on two extreme positions on the scale from the centre, now under equilibrium the scale will be horizontal...now my question is if one of the weight is lowered by action...

Hi, I'm new on this website and it seems great :p So, I'm struggling with something really simple... trusses analysis. I'm struggling with moments etc , I've just drawn an example linked in this post , could you try to find the reaction forces (roller pin etc) with some explanation ? Thanks

I have been boggled by something for a while now. It pertains to the forces acting on two cranks in an opposing piston engine. So let's just assume the pressure remains constant in the cylinder(for simplification). Now half way through the cycle one piston is acting on a 3" moment arm with a...

Homework Statement I have a 6 meter long beam that is supported by a roller at 0m and a pin at 6m. There is a triangular distributed load that begins at 0m to 3m which is 2kN/m. (Max load is at 0m) There is an additional triangular distributed load that begin at 3m which mirrors the first...

Homework Statement problem in in the picture Homework Equations I can't understand some parts of the equation. The Attempt at a Solution

Homework Statement "A uniform plank 3.0m long and a weight of 200N is supported horizontally and symmetrically across two trestles, A and B, placed 2.0m apart. Calculate the reaction force of each trestle. What is the maximum weight that can be placed at one end without the plank tipping...

Homework Statement Do the following have equal moments about A? Homework Equations T=rf The Attempt at a Solution Yes because using L*cos(30), they will be the same? What is your reasoning?

Are my calculations for R1 correct.

1. The scenario is the same as this (with a circular cross section): http://upload.wikimedia.org/wikipedia/commons/c/cf/Poutre_flexion_deviee.svg 2. Do I simply calculate the stresses from each bending moment and add them together? Or take the resultant vector and calculate...

I had to clear this up since there were many threads with the wrong analysis of this problem. Lone pair electrons DO have and affect on dipole moments. Lone pair electrons do have an effect on the net dipole moment of a molecule. A dipole moment is the product of the magnitude of the partial...

Inertia -- Moments of Inertia of a rigid body (different axes) Here is the problem http://imgur.com/pL6Bdgw So I missed class today because I was studying for a genetics test. I don't need the answer or anything but I was wondering what the general rule for inertia that I would use for...

Homework Statement Internal moments need to equal external moments, work out the total of the internal moments. The object has a mass of 2 kg Homework Equations I have obtained the moment about I (labelled as MI) + Iα The Attempt at a Solution the moment about I (MI)...

How to Take the sum of moments ! Homework Statement Hi i am doing static equilibrium exercises in textbook. Homework Equations But I don't know how to find sum of moments at P when its come to angle. This is a drawing The Attempt at a Solution I have No idea ! I was...

Hello, I'm very confused with this problem and need some help and direction on how to write dynamic equations of motion. The problem is as follows: Write the dynamic equations of motion for muscle force Fm, hip force Fj in the normal direction n towards rotation center along the -r direction...

Homework Statement Just in case my interpretation of the diagram does not give a clear representation, here is a link to all of the questions. http://imgur.com/a/jsv9e The question begins by asking me to state the necessary conditions for a body to be in a state of equilibrium. It is a...

Please refer to the attached image.The concept of MGF still plagues me. I got an invalid answer when i tried this. What i did was: $ \int e^{tx}f_{X}(x)dx $ = $ \int_{-\infty}^{+\infty} e^{tx}(p \lambda e^{-\lambda x} + (1-p)\mu e^{-x\mu})dx$ I was a bit wary at this point, because it...

Moments -- How are they actually calculated? Hello, I have a question. Is the moment calculated: Force times the distance or Force's perpendicular component (to axis) times the distance. For example, let's say I have a stick. Pulling on it is not moment. So if I push at the...

Need help on some questions -- Moments, Bearings & Trusses Hi guys, just have some general queries on a couple of problems : 1) http://i1097.photobucket.com/albums/g357/princejan7/reactiondirection_zps85d28093.png They got the moment of the force BC about A by splitting into components...

1. How do I find the force of A and B. I am taking moments at A but I am not getting the correct answer. (More Details below of attempt)Homework Equations Ʃ Of Clockwise Moments = Ʃ Of Anti-Clockwise Moments Ʃ Of Upward Force = Ʃ Of Downward ForceThe Attempt at a Solution (THIS IS WRONG BUT...

Homework Statement knowing the tension in cable AB is 570 N, determine the moment about each of the coordinate axes of the force exerted on the plate at B . This link has a picture...

Homework Statement http://imageshack.us/a/img812/8836/5tfn.jpg Uploaded with ImageShack.us Find F such that the moment around A will not exceed 1000N*m for any value of θ. Homework Equations M = fdThe Attempt at a Solution I got the right answer, I found the distance of a -> b AB= √( (2^2)...

The problem statement A uniform rod of length 2m and mass 5kg is connected to a vertical wall by a smooth hinge at A and a wire CB as shown. If a 10 Kg mass is attached to D, find: a) the tension in the wire b) the magnitude of the reaction at the hinge A. attached is my copy of the...

Homework Statement I'm having problems with understanding how to use the right hand rule as it applies to forces and determining moments. If I understand correctly, The fingers point in the direction of the force, then curl in the direction of r, but I'm not sure what r would be in this...

Are there simultaneous moments? I know that relativity states that demetion is proortional to velocity ant that mass is also demension of time but the real question is are nearness values absolute? Is there such a thing as objective nearness in strict time? Thought experiment: A species...

The figure below shows a section of the human forearm in equilibrium. The weight of the object in the hand is 60 N. The centre of gravity of this object is 32 cm from the elbow. The bicep provides an upward force of magnitude F. The distance between the line of action of this force...

I've just finished watching an interview with Richard Dawkins, where he describes what he considers to be transcendent moments during his life and career. I'd like to know what experiences members here have had which you may also describe as transcendent, and to what extent you would attribute...

Really need help with these two questions. I have been working on them for some time and just can't seem to make any significant progress1) X is a continuous random variable with density function f(x) = (θ + 1)x^θ , 0 < x < 1 and 0 elsewhere Derive both the method of moments estimator and...

Forces F1 =j + 3k, F2 = j + k and F3 = 2i + j act at the point (0; 1;2), (1;0;3) and (1;1;0) respectively. (a) Find the total force and the total moment about the origin. (b) Find an equivalent system of forces consisting of a single force acting at the (1;0;0) together with a couple.Ok so for...

Homework Statement Let X1, X2,..., Xn be a random sample of size n from a geometric distribution for which p is the probability of success. Let m denote the sample mean. Use the method of moments to find a point estimate for p. Please write your answer in terms of m. Homework Equations The...

My main issue here is determining the correct reaction force, I'm truly lost as to where I'm making a mistake? The question is: A uniform rod of length 2m and mass 5kg is connected to a vertical wall by a smooth hinge at A and a wire CB as shown. If a 10kg mass is attached to D, find: The...

Homework Statement Firstly, I know posting images and asking for help is generally frowned upon, however in this case given the number of diagrams and equations involved I'm hoping it's warranted. So we're given a diagram as at the top of the attached image and we're asked, given most of the...

In a two-dimensional statics problem involving finding a moment about a point, I don't understand how the result is either in the positive/negative z direction. I realize moments are found by the cross product, and the cross product requires the answer to be perpendicular to the plane that...

Hi all, currently having a few issues with understanding a few aspects of questions involving normal reactions at angles. Just an example of where I am going wrong: 'A loft door OA of weight 100N is propped open at 50 degrees to the horizontal by a strut AB. The door is hinged at O...

Is it possible that for a random variable X there exist no p in (0,1) so that EX^p < ∞ ? Is there any example?

Does any moving charge generate a magnetic moment? I thought so because a moving charge generates a magnetic field.

What formula do I need here?Starting from the sum $I = \sum\limits_{\alpha = 1}^Nm_{\alpha}\rho_{\alpha}^2$ and replacing it by the appropriate integral, find the moment of inertia of a uniform thin square of side $2b$, rotating about an axis perpendicular to the square and passing through the...

Homework Statement I'm not sure on the principles of moments Homework Equations The Attempt at a Solution Is it just that moments are a turning force?

Moments -- Balancing a weighted meter stick A meter stick is found to balance at the 49.2cm mark when placed on a fulcrum. When a 46.0g mass is attached at the 14.7cm mark, the fulcrum must be moved to the 38.7cm mark for balance. What is the mass of the meter stick? I know I have to use...