Moment Definition and 1000 Threads

Hi, I'm setting up an equation for initial gravitational potential energy, and I'm just wondering what the moment of inertia, I, would be for a water bottle rolling down an inclined ramp? Is it mr2 or ½mr2 Or would it be something else?

Is there a method to calculate inertia tensor form principal axes moment of inertia? Like now we have moment of inertia: (Ix,Iy,Iz)=(20,18,25), and hot to calculate the inertia tensor like (Ixx,Ixy,Ixz Iyx,Iyy,Iyz, Izx,Izy,Izz)? I have read about this page several times, but still have no idea.

Imagine an aircraft of which the its wing is connected to its landing gear by means of a hinge (joint), and then the gear suddenly gets stuck midway. If, subsequently, the aircraft makes a turn around its longitudinal axis (see picture), it seems to hold true that then the angle between the...

Consider the magnetic field B generated by a magnetic dipole. The intensity of B measured along the axis of the dipole, at a distance of 10 cm from the dipole itself, is 1.0 10-5 T. What is the size of the magnetic dipole moment? (μ0 =4π10-7 mkg/C2) a) 0.050 Am2 b) 5 10 -4 Am2 c) 0,1 Am2 d) 1 10...

Homework Statement Two uniform 150 N rafters rest on frictionless floor, held together by a rope. A 500 N load is held at their apex. Find tension in the tie rope. Homework Equations ##torque= rFsin \theta =Force*Moment Arm ## The Attempt at a Solution The angle ##\theta## in the picture...

Is the time since the Big Bang the same for every point in our universe? If so, does that imply there really is a "present" moment everywhere and not just in my immediate locality?

Hi guys... I am creating a parametric spreadsheet to predict the behaviour of a sign post when subject to a specified wind speed for a uni assignment . Currently half way through creating the spreadsheet and one of the questions requires me to calculate a wall thickness of the pipe using the...

Hello, I was recently given the task to find experimentally the moment inertia of a sphere. I thought of rolling the sphere down an inclined plane and applying conservation of energy to the sphere. The equations i came up with are: mgh = 1/2mv2 + 1/2Iω2 solving for v^2 we come up with the...

Homework Statement Good afternoon, I hope someone could help me with this problem, it is killing my head. I have an aerogenerator, I already find the torque excerted by the air (75.8N) and the force transmitted by the gear (1010.6N). The problem comes when I try to draw the free body diagram to...

Homework Statement A square plate is of mass M and length of edge 2a. Its M.I about its centre of mass axis, perpendicular to its plane is equal to I(1). Four identical disks of diameter a are cut from the plane. The MI of leftover square about the same axis? Homework Equations 1) MI of...

So I have been having a bit of trouble trying to derive the moment of inertia of a solid sphere through its center of mass. Here is my working as shown in the attached file. The problem is, I end up getting a solution of I = (3/5)MR^2, whereas, in any textbook, it says that the inertia should...

Supposing that the total mass + energy content of the Big Bang was 100 in energy-equivalent terms. What would we consider its energy-equivalent mass to be today? If the universe is today accelerating and that acceleration is not abating, then (naïvely perhaps...) its (dark-energy) potential...

Homework Statement Moment of inertia of a metal plate (center at origin) which was a square before 1/4th of it was cut off (4th quadrant), about three points a)- top leftmost corner in 2nd quadrant b)- origin and c) (where the right-lowest corner used to be in 4th quadrant) ranked in decreasing...

Homework Statement a magnetic moment of U = 1 (i) + 2 (k) , surrounded by a magnetic uniform field of B= 3 (i) + 4 (j) - 1 (k) find the potential energy in mJ ? Homework Equations dot product of 2 vectors ( ui*bi)+(uj*bj)+(uk*bk) = or finding the module of both vector and doing AB...

Homework Statement Three slim rods with the same length L are placed in a inverted U shape, as the figure shows. The masses of the vertical rods are the same, while the third bar has the mass 3 times bigger than the first or the second rod. The rods' thickness should be ignored. Find the moment...

How large was the universe at its moment of creation? Do we have a real answer for this? If so, how was this found out?

I JUST spotted the ISS with my powerful binoculars, How luck I am... :woot: I was looking at Sirius and just then a streak of non twinkling light passed through, when I ran to desktop to check ISS tracker i saw it was just over India... I feel very lucky to see the greatest project of mankind...

"Calculated the total magnetic moment of a hydrogen atom in the ground state in a weak magnetic field which arises from hyper fine splitting of the ground state. How many beams does hydrogen produce from a Stern-Gerlach analyzer with a weak magnetic field?" I've calculated the magnetic moments...

Homework Statement :[/B] A uniform wire of linear mass density λ having three sides each of length 2a is kept on a smooth horizontal surface. An impulse J is applied at one end as shown in the figure. P is the midpoint of AB. Now answer the following questions. 1) The angular velocity of system...

Homework Statement Homework EquationsThe Attempt at a Solution I am confused. It looks like the couple forces are at a angle pointing to the x axis. So i did moment about a axis of that angle. I found this angle/axis unit vector to be (-0.6i -0.8j) Then i found the moment couple about the x...

Homework Statement Beam spans 40 feet, with uniform loading of 500 pound/feet and a point load of 4000 pound at mid span. Support A is roller, support B is pin. How to determine the maximum moment and maximum deflection due to the loads. Use Force method Since it is a Determinate...

Homework Statement 1. Homework Statement An uniform disk of mass m, thickness L and radius r is suspended from the ceiling by a wire. It is attached to the disk at a distance, d from the center of mass, so that it inclines at an angle A to the vertical. What is the moment of inertia of the...

Homework Statement This is from Griffith's Introduction to Electrodynamics, where the book is deriving the magnetic dipole moment from multipole expansion of the vector potential The vector potential of a current loop can be written as $$\mathbf{A(r)}=\frac{\mu_0 I}{4\pi} \left[ \frac{1}{r}...

Homework Statement I'm trying to determine the torque vector and quantity of said vector per the sketch attached. Homework Equations T=fd[/B] The Attempt at a Solution T = 100 lbs x 2 f2f T= 200 ftlbs But my real question is where is that Force being applied at is it the attachment point...

Homework Statement Find moment of inertia of a washer with a hole of radius r/2. Homework Equations Moment of inertia = integral of x^2 dm γ = m / L The Attempt at a Solution I think I can find the moment of inertia of the washer using integral of x^2 dm. So, I know my γ = m / L = m /...

Homework Statement The moment of inertia about an axis through the center of mass of a system consisting of two masses 3.0 and 5.0 kg connected by a rod of negligible mass 0.8m long is Homework Equations [/B] I = I1 + I2 The Attempt at a Solution I added all the moments of inertia of the...

Homework Statement A meter stick has a mass of 0.2kg. A small hole is bored in it at the 10cm mark so the meter stick can be hung from a horizontal nail. The moment of inertia of the meter stick around an axis at the 10cm mark is Homework Equations m = 0.2kg I = mr^2 The Attempt at a...

Homework Statement Homework Equations How will we find the perpendicular distance between the wall and the centre of mass of the slab? How will we calculate the total downward force exerted by the cables on the slab? I thought much over both the cases but was not able to find any solution...

Homework Statement Homework Equations How do we calculate the value of F? The Attempt at a Solution Since for an object to be in equilibrium, F1D1 = F2D2 so 7.2 x 1 = F x 8 F = 0.9N, I am pretty much confused with the answer I worked out. If I am wrong or if I am right, please explain me the...

Homework Statement Consider a half disk (of uniform density) with the flat end lying on the x-axis, symmetric about the y-axis (i.e. being cut into two quarters by the y-axis). Calculate the moments of inertia about each of the axes. Homework Equations $$I_{rr}=\sum_{i}m_ir_i^2$$ The Attempt...

Homework Statement , [/B] Please see the attached picture. But I'm trying to do is figure out where this moment would be created and how much torque would be applied based upon this example. Homework Equations T = fxd The Attempt at a Solution [/B] I would suspect that any weight added to the...

Homework Statement Homework Equations I=1/12*bh^2+Md^2 The Attempt at a Solution for the highlighted 600mm^2 (and the 300mm^2 below) in the middle of the page, when finding the moment of inertia, what the solution used is an area, yet for related formula required the use as for mass in the...

1. The problem statement, all variables, and given/known data Good day I am preparing for a strength of materials exam and I can't seem to solve this problem. I am unsure if the section below the neutral axis is fully plastic before the edge of the flange experiences the yield stress. Could...

Homework Statement I am trying to model a structure that has moment connections between some beams and columns, and shear connections between the remaining beam and columns in 3D. The software I am using (S-Frame 11) gives me an error when running the analysis for the nodes that I have...

Hello Everyone, From what I read, an airplane's wing always has a forward-pitching moment which is a torque that tends to rotate the plane nose down. Is this moment nonzero for any angle of attack (zero, positive, negative)? A torque needs a force and a distance (lever arm). I think the force...

<< Mentor Note -- Thread moved from the technical forums, so no Template is shown >> Hi , Please I have to understand the solution of an exercice about calculating bending moment in penstock : It is assumed that maximum moment from penstock beam bending occurs at supports. The bending moment M...

Homework Statement Two planets are masses stuck to end of long thin rods. These model systems (Rod + mass) will be rotated by a motor at their other end of the rod, as shown in the figure. the length of the rod is proportional to the orbital distance of the planet, and the mass at the end is...

Homework Statement Homework Equations Sum of force = 0 / Sum of moment = 0 The Attempt at a Solution Why don't the solution consider force P at join C for body CD? And it considered both force P and reaction force C at join C for body AC... So force C doesn't seems to be the net force at...

In my EM class, this vector identity for the angular momentum operator (without the ##i##) was stated without proof. Is there anywhere I can look to to actually find a good example/proof on how this works? This is in spherical coordinates, and I can't seem to find this vector identity anywhere...

When neutral atoms become polarized from ambient EM radiation, does this automatically imply that electrons have shifted orbitals,or do they remain in the same levels but become deformed? Thanks

Homework Statement Homework Equations I = mr^2 (point mass) The Attempt at a Solution I wasn't sure how to calculate the moment of inertia of this triangle if the axis is going through one vertice perpendicularly. Do i calculate the inerta of 2 sides with Inertia of a rod and the 3 side as...

For an undergraduate project, I need a magnet with a magnetic dipole strength of 0.3 A*m^2. However, all distributors I can find only list their magnets in terms of "pull force" which appears to be defined as the force between a magnet and a steel plate. How do I find a magnet with the dipole I...

Homework Statement I shall determine the course of the normal force, the lateral force and the bending moment. And then sketch that as a graph Homework Equations All Moments are 0 All Fx = 0 All Fy = 0 The Attempt at a Solutionhere is my clear cut (is this the right Word in English ? :)...

I need to find the maximum contortion of a torsion spring, for a given system. Most of the assignment I have done correct, but this last part I simply cannot get right. The pictures below is what I have used, but they are probably not necessary for this problem. In prior parts of the...

I have some serious issues trying to understand the idea of the spin in the context of the Stern-Gerlach experiment and would appreciate some assistance! Assuming that a homogenous magnetic field ##B## in the "North-wards" ##z##-direction, assume that there is a magnetic dipole moment ##\mu##...

Hello, this formula was given to me in an exam to find the moment of inertia of an I beam, https://ibb.co/jY7ZKG However this formula seems to give a different answer to the standard bd^3/12 method, is the formula in the image wrong ? Thanks

Homework Statement A thin stick of mass M = 3.9 kg and length L = 1.8 m is hinged at the top. A piece of clay, mass m = 0.3 kg and velocity V = 2.9 m/s hits the stick a distance x = 1.60 m from the hinge and sticks to it. What is the angular velocity of the stick immediately after the...

Good day all, I have an issue regarding the theoretical concept regarding the stress generated by the skew bending in a rectangular cross section for example the formula used to calculated the stress is while when it is a circular cross section we have the following formula I really...

In force-couple system equivalence, We can show that two systems are equivalent if the resultant force in both are equal and that it has the same line of action. So Rx1 = Rx2, Ry1= Ry2, Ma1 = Ma2 Now my book says we can use another form of equation: We can choose 3 point and find the moment...

<<<moved from another sub forum, no template>>Hi, I need to calculate the moment of inertia for the component in the attached image so that i can calculate the angular momentum. Is it possible? Overall i am trying to calculate the forces on this lug as it passes around a 3" radius at 2M a...