Moments Definition and 598 Threads

Hi, My problem is with A.P. French vibrations and waves question 3-10, part (b). Question 3-10(a) A metal rod, 0.5 m long, has a rectangular cross section of area 2 mm2. With the rod vertical and a mass of 60kg hung from the bottom, there is an extension of 0.25 mm. What is the Young's...

haruspex submitted a new PF Insights post Frequently Made Errors in Mechanics - Moments Continue reading the Original PF Insights Post.

Hi I am attempting a question on moments and beams. I have attached the question and my solutions so far. But having trouble completing d) and e) Can someone show how to work out bending moments and the point of contraflexure? [PLAIN]http:// any help is appreciated thanks

Hello Everyone, Kindly, may anyone please tell me what are the allowed and forbidden transition dipole moments between different molecular electronic states in diatomic molecules? Thank you so much in advance...

Homework Statement The problem is question 4) iii) B) found in the attachment below. Homework Equations • sum of c.w moments=sum of anti c.w moments. • moment of a force about a point= force x perpendicular distance between the line of action of the force and the point. The Attempt at a...

Homework Statement A square plate has a side length of 1.2 m. An applied torque of 300 N · m gives the plate an angular acceleration of 4.8 rad/s2 about an axis through the centre of the plate. Determine the plate’s mass. Homework Equations t = lα l = 1/12M(l^2 + w^2) The Attempt at a...

Hey there, In my statics class we're just finishing up moments of area or moments of inertia as they're being called. I can do the math and figure them out just fine but I have no clue what I'm actually finding! What is it? I am having trouble actually conceptualizing what it is that I'm...

Homework Statement The weight of rod AB is 4[N] and that of piece D is 10[N]. the moment at joint C is 1.8[Nxm]. what is the weight of rod AC. Homework Equations Moments: ##M=F\cdot L## The Attempt at a Solution Rod AB doesn't contribute to the moment at C: $$10\cdot 15+180=W_AC\cdot...

building a small portable crane to be used on a small boat that will be used to retrieve a sediment grab (weight = 200lb) at a depth of 50m

Homework Statement The weight of the beam is 2000N, the masses: m1=200kg, m2=300kg. What are the tensions in the ropes. Homework Equations Moments: ##M=F\cdot L## The Attempt at a Solution Moments around A: $$\mbox{and}\left\{\begin{array}{ll} 1.5\cdot T_B+1.2\cdot T_B+0.6\cdot T_A=1962\cdot...

Homework Statement The right angle boom which supports the 230-kg cylinder is supported by three cables and a ball-and-socket joint at O attached to the vertical x-y surface. Determine the reactions at O and the cable tensions. Homework Equations M [/B]= r x F unit vector =...

In the above figure, a small weight is placed at 2 cm (0.02 m) from the center of the rectangular prism. Let's call the mass of this small weight (M1) and the mass of the entire body including the small weight (M) Given the dimensions above, I want to know how to calculate the height of center...

Homework Statement Two Forces are acting concurrently and their resultant is 500 N as shown in figure on the right. Determine P and the angle P makes with the x-axis? 2. The attempt at a solution Is my answer correct?[/B]

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...

Homework Statement A cylinder with two rods coming out of it. The ends of the rods are fixed. A force is applied through the center of the top surface of the cylinder. What are the reaction forces and moments at the rod ends? Here is a diagram of the scenario: http://www.imgur.com/Tsdhmzf.jpg...

Homework Statement Problem shown as image jan2010 Q5.jpg Q5. a) Homework Equations Also shown in image The Attempt at a Solution Made a cut between A and the z-line, so ∑M = 0 = M - wx(x/2) = M - (wx2)/2 ⇒ M = (wx2)/2 and d2y/dx2 = -M/EI ∴ d2y/dx2 = - (wx2)/2EI So dy/dx = ∫ d2y/dx2 dx =...

Hi, question and solution attached. I'm having trouble converting the second equation in 2 (b) to the corresponding bending moment equation. I have worked out everything else, I'm just unsure how the '-1562.5N' part is calculated. http://snag.gy/Uqrel.jpg Help is much appreciated, thanks!

How do I determine the support reactions at A & E in this example? Help is much appreciated.

Homework Statement Calculate the tension in the rope, T, in the diagram below: http://imageshack.com/a/img905/2848/yMC01l.png Homework EquationsThe Attempt at a Solution The 'beam' is a stable structure, thus the resultant forces be equal that are acting upon the beam. So, I calculated the...

HELP! how to calc the force needed to bend this fixed beam channel by 4mm at 'F'http://www.engineersedge.com/engineering-forum/attachment.php?attachmentid=1254&stc=1

Hello everybody I am new here and I would like to ask a simple question about the centre of gravity and how it changes with mass, size , weight , density. etc.etc I would like to understand how this phenomenon happens and I have tried searching online to no avail so please help me understand how...

My instructor was talking about allowed transitions for IR spectroscopy and how you can predict them relatively well using PIB wavefunctions. It was stated that you could solve for the probability of a transition moment to determine if a transition is forbidden or not. <μ>=∫ΨfμΨidτ...

Please Help! I've been working on the problem for all day now and can't seem to get it right. One of my attempts came close to the answer in the back of the book but was off by about 4, the it should be at 30 degrees M=5860lb ft, and I got 5856. Along with this I have to enter the equations into...

Homework Statement The question is as follows: How much force should I apply if i want to have a wheel of mass 2kg and radius R to pass over a step with height h, where R is twice as big as h. I attached a picture of the problem for reference. Homework Equations I am not sure but I think I...

So i know how to work out moments sort of but i am confused on what i am actually working out. So i get the answer in Newtons a Metre, but what does that mean exactly? And why is it that when i divide the other side of a levers length by this it gives me the force on the other side?

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...

Say I have a uniform beam supported by 2 bricks and I attach an object with a certain weight at one end of the beam so it starts tilting. Why is the beam still in equlibrium (sum of moments about one of the bricks is equal to 0) if it is tilting?. I've seen this exercise on youtube and I'm still...

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...

You know you've done it. You can't find something that you're looking for and when you finally find it, you wonder why you didn't look there in the first place. Me yesterday: I was getting ready for an afternoon run. As I am going out the door, I get my watch and a key to the door. But...

Homework Statement W= 3kip/ft. Find the shear force and moment at C. Homework EquationsThe Attempt at a Solution Skipping some initial steps, I found the reactions to be Ax=0 and Ay=9 These are known to be correct. Now, slicing the beam from a to c. I get Ay=9. Now I take 3(1/2)6= 9 from...

Homework Statement Homework Equations I= ∑ miri^2 ? The Attempt at a Solution I'm not sure on how to start this problem. How exactly do I know which one is IA, IB, IC since it didnt specify? Can somebody please hint me in solving this problem?

Homework Statement The assembly shown is used to control the tension T in a tape that passes around a frictionless spool at E. Collar C is welded to rods ABC and CDE. It can rotate about shaft FG but its motion along the shaft is prevented by a washer S. For the loading shown, determine (a) the...

Homework Statement Homework Equations Moment = force * perpendicular distance The Attempt at a Solution My book says the answer is 59N, I don't get why my method failed, I use the exact same thing for problems such as calculating the contact force produced by the ground at the end of a...

Hi Folks, Is it possible to calculate the principle moments of inertia acting along the principle axes of inertia given the moments of inertia and their directional vectors. Ie , I have the following information Moments of inertia ##J_1, J_2,J_3=18kgm2,15kgm2,6kgm2## and the directional...

In the structure shown, a cable is attached to the 50 kN weight and to the beam A-D at point B. If the horizontal uniform beam weighs 8 kN/m, determine the following: (a) The horizontal and vertical component of the force that the pin at D exerts on the beam A-D. (b) The force in the cable. ...

Homework Statement I have a laminate subject to 3 forces and 3 moments: Nx = normal force resultant in the x direction (N/m) Ny = normal force resultant in the y direction (N/m) Nxy = shear force resultant (N/m) Mx = Bending moment resultant in the x direction (Nm/m) My = Bending moment...

Homework Statement The mass of a homogenous thin plate is 36kg. Determine it moment of inertia about the x axis Homework Equations Parallel axis theorem: Ix = Ix' + d^2*m The Attempt at a Solution p = m/a = 36/0.36 = 100 Because the density is homogenous, I found the mass of the first...

Homework Statement I have to solve for legs AB, CB, and the tension in DB. The weight of the fish net is 200 kg. Homework Equations Sum of moment = 0 Sum of force in x,y,z directions = 0The Attempt at a Solution I have no idea what to do. I've tried using AB and CB as two force members...

2 uniform roods each or weight W and length L are welded together so that angel ABC is 90, the two rods are hanging in equilibrium from a fixed loin at A by a hinge which allows the rods to swing in a vertical plane. by taking the moments about the hinge find the angle that AB makes with the...

Homework Statement A body (let's call it a rod for simplicity) is in frictionless space, and is composed of 4 smaller sub-rods fused (cannot break) end to end. Each sub-rod has a unique mass (m1, m2, m3 and m4) and length (l1, l2, l3, and l4), but they all have the same diameter d. A force...

I did a search, and didn't see a thread for this.. https://www.youtube.com/watch?v=watch?v=m_VURr6jnWQ

[SIZE="4"]Definition/Summary The moment of a vector is the cross-product of the position vector with that vector (e.g., a force or momentum vector). So it is is a vector (strictly, a pseudovector), and obeys the rules of vector addition. Moment of momentum is more usually called angular...

So, I've been looking into orbital angular momentum and magnetic moments, (which, at least in normal space with a normal angular topology seems limited to integer values of spin). (My model so far has been a parabolic potential harmonic oscillator in 3d, and the sort of spinning modes you can...

For figure 1.2, if you take moments at the point where H acts, then you get (assuming moments are positive anti-clockwise): -RCos(theta)(0.4) + 60(0.2) = 0 Rearranging gives: Rcos(theta) = 30 However, according to the mark scheme (which takes moments at the point where R acts)...

The question I'm attempting to do is part (a): http://www.picpaste.com/struc1-z7FJMCcF.jpg which translates to: determine distribution of moment, The beam is elastic and has constant EI throughout its entire length. Now part of the solution looks like this...

So My wife and I just got around to watching this last night and it was decent enough if you put your disbelief in cyrostasis but hey that's Strek Trek in general. That being said, and knowing there is no semblance of reality to the science, Of all the scenes that would have bothered me, it was...

Homework Statement hi guys this is an image of the rear wheel of a push bike going into a corner as well as what i think are relevant forces, i need to calculate the moments or torque at A (the contact patch) and B (the hub centre) this is to calculate the force on the left hand side of the...

hi guys this is an image of the rear wheel of a push bike going into a corner as well as what i think are relevant forces, i need to calculate the moments or torque at A (the contact patch) and B (the hub centre) this is to calculate the force on the left hand side of the frame and right hand...

Hi I have been looking for some simple equations that describe the turning moments on the rotor as wind direction changes. I know this can be relatively complex but I am looking for simplified equations. Has anyone got any information where I can find these? The wind turbine is a small...

In a dipole, p = qd is the dipole moment. q is the magnitude of either charge, while d is the distance of separation. I was just wondering what differences in properties would be evident if both charges in the dipole were not the exact negatives of each other. For example, if you have a positive...