Moments Definition and 626 Threads

##\sum M_{A} = F.(d+d` )-F(d+d` )-F.d## I am getting negative answer. Where I am doing wrong in summing moments for this diagram?

So I let x be the distance from P. I then considered moments about R and got this: 1) (40g)(x-3) = 40gx - 120g and this is anticlockwise 2) (30g)(0.5) = 15g and this is anticlockwise 3) (2.5g)(2) = 5g and this is clockwise And then by equating clockwise and anticlockwise I get this: 40gx -...

I know the answer and how to go about it the normal way. Could i possibly use the nose to tail method of finding the S value. Although it does not say in the question there are three forces on ladder support force , weight, support form the wall. So could i make a triangle then use sine rule...

Hi All, Everyone knows so called "fictitious" forces, also known as "inertial" forces. They are forces felt by some mass point placed in a non-inertial frame. For example: a ball in a moving car or in a carousel. Maybe most intuitive fictitious forces are centrifugal forces, but there are also...

Homework Statement Homework EquationsThe Attempt at a Solution problem number 10

Does electrons or other particles attracted towards a magnet due its magnetic momentum?

Homework Statement Homework Equations ∑MA = 0, where A is the pin. Tx = Tcos150 Ty = Tsin150 The Attempt at a Solution I've drawn in the 100kN force of the beam's weight, and identified that ∑MA = 0. I attempted to find the moment arm, but really wasn't sure how do to it, or if it would even...

Hello I am doing a shaft design layout for a spindle to minimize deflection and I have to calculate the area moment of inertia for a shaft overhang.The shaft overhang is the distance from a bearing to the end of the shaft. Here is a picture detailing the location of the overhang. The black...

Hello, I would like to demonstrate the 2 below equations (##eq(1)## and ##eq(2)##) concerning the first and second moment of Radiative Transfer Equation (RTE) (where ##I_{\nu}## represents the specific intensity) : Starting from the definitions : ##J_{\nu}=\dfrac{1}{2} \int_{-1}^{1}...

1. Find the value of tan φ to 2 sf where φ is angle made by line of action of reaction force at hinge above horizontal. https://isaacphysics.org/questions/trapdoor_num Part B Angle of reaction forceHomework Equations Mass of uniform trapdoor: m=4.0kgm=4.0kgThe trapdoor is held open making an...

Hello All, I want to apply moments to Revolute Joints in Explicit Dynamic Analysis. But i could not find any option to apply moments. I saw an youtube video, from which it is cleary know that it is possible to apply moments to revolute joints under initial conditions. But i don't know how they...

What are some moments you have seen where an opponent helps their opponent in some way, such as like when a enemy robotics team gave my team rubber to assist with picking objectives up allowing us to do better that year or when another team let us borrow an expensive router when ours broke so we...

Hello I am a bit confused how to calculate the shear force and bending moment graph for a beam under point loads, distributed loads and bending moments. Is the discontinuous functions the best method to solve such problems? Can anyone outline an approach? I don't understand for example how...

Homework Statement I'm trying to figure out the mass moments of inertia for a hexagonal prism, with the z-axis being longitudinal. I'm trying to recall my calc 3 from 2 years ago and am failing miserably. I know the height of the prism is h. Each hexagonal side is length a. The prism has...

Homework Statement This is more of a question of applying the correct principles to a range of problems involving a horizontal rod hinged to a wall that is then supported by another rod. The support rod is also attached to the wall from above or below and then attached to the horizontal rod, so...

Homework Statement Homework Equations inertia equations The Attempt at a Solution I think the answer for this is B) or D) but I am not sure what the sentence "a special solid cylinder in which the density is proportional to the radius" means... The solid sphere has little inertia because...

Hello, #1 As my teacher explained "T=F•r•sin<" all clear so far. When i attempted to apply the formula it crossed my mind that the unit of T is (N•m), if so how do we solve for distence 0< r < 1. #2 Another question if the unit is {(kg•m)/(s^2)}•m why did he represent moment with Newtons...

Hi...What is a contact force and where is it labelled in a diagram showing a beam pivoted?

Hi everyone, This is not really a homework question per se since it's not an assignment. Basically, our physics professor gave us a 100+ page syllabus filled with example questions and solutions and I am practicing with them by doing them one after the other. This one question I'm having...

Homework Statement Homework Equations in photos The Attempt at a Solution [/B] First approach: Second approach: The two approaches used net force and net moment respectively in order to find reaction force of O, yet they got different answers. Why? Thank you very much!

Homework Statement Homework Equations Angular momentum = moment of inertia * angular velocity Change in angular momentum = impulsive moment v^2=u^2+2as The Attempt at a Solution First I used v^2=u^2+2as to find the velocity of the particle the moment the string goes taut. I got v=\sqrt{8ag}...

Homework Statement a round bar,125mm in diameter , is to be used as a beam. if youngs modulus for the material E=200x103 N/mm2 Calculate: i)Maximum allowable bending moment(12marks) ii)The radius of curvature at the point of maximum bending moment(8marks) Homework Equations σ/y=m/I=E/R...

Homework Statement A uniform cylinder has mass m kilograms and radius 5 metres. Calculate the magnitude of the horizontal force Fthat needs to be applied on its axis to start it rolling up a step of height 2 metres, as shown in the diagram Homework Equations Anticlockwise torque=Clockwise...

Homework Statement A 200N force is applied to the handle of the hoist in the direction shown. The bearing A supports the thrust (force in the direction of the shaft axis), while bearing B supports only radial load (load normal to the shaft axis). Determine the mass 'm' which can be supported...

Homework Statement The board shown below is being held in equilibrium in the vertical plane by three smooth rods at A, B, and C Determine the magnitudes of forces at A, B, and C in terms of the weight of the body, W. Homework Equations Moment = f*r Here's a diagram The Attempt at a...

just stumbled across this article I am sure other tech types like me will appreciate this article ... http://www.mro-network.com/engineering-design/understanding-today-s-antenna-complexitiesenjoy cheers Dave

Verify the given moment(s) of inertia and find x double bar and y double bar. Assume that the lamina has a density of p = 1, where p is rho. The diagram given is a circle with radius a. The entire circle is shaded. We are also given I_o = (pi•a^4)/2, where I_o is the moment of inertia about...

Verify the given moment(s) of inertia and find x double bar and y double bar. Assume that the given lamina has a density of p = 1, where p is rho. I_x = (bh^3)/3 I_y = (b^3h)/3 I found the mass to be bh. x double bar = sqrt{(bh^3)/3 ÷ bh} x double bar = sqrt{b^2/3} x double bar =...

Homework Statement A uniform board of length 90cm is pivoted at a hinge at one end. It is kept level by an upward vertical force T applied at the opposite end. The weight of the board is 6N. Take moments about the hinge to find T when the board is level. Homework Equations Moment = Force x...

Find the moments of inertia about the x-axis, y-axis and the origin. Also, find the radius of gyration about the x-axis and y-axis. y = 0, y = b, x = 0, x = a Rho = ky 1. Is ky the density function? 2. Do I integrate over dxdy or dydx? 3. Are the limits of integration y = 0, y = b, x = 0...

Homework Statement Homework Equations This would be the part I think I'm missing The Attempt at a Solution In the fourth line, Ix, where is the justification for multiplying 1/3 by the first term? I believe they are using the center of inertia of a rod, which is mr2 and the first term...

Hi, I need some assistance understanding moments of inertia. I am doing some review for an upcoming exam, however I am slightly stumped by this question. I have already tried googling "moments of inertia" to try and understand the concept better, but I am having issues knowing when to apply...

Homework Statement Homework Equations The equations are all given The Attempt at a Solution This isn't really a homework question... it's solved, but I'm having a hard time following it. I don't understand where the first term: -a(kaθ) comes from. I can see it's the moment relation...

Why are kinetic moments not included in the regular summation of the moments? In other words why is the equation ∑M = ∑Mk and not ∑M + ∑Mk = 0 ? I guess it would help if someone could explain exactly what a kinetic moment is, and why it is equal to the summation of the moments due to external...

Why don't we include the kinetic moments in the summation of the moments of a rigid body? In other words, why are the kinetic moments on the opposite side of the equation as the moments due to external forces? I understand that the math works out but it's not making sense to me conceptually...

Homework Statement In this question , we can see that in teh second picture , the 12.86kNm is in clockwise direction at the right of span BC . Homework EquationsThe Attempt at a Solution In meachnic of materials , i learned that when the beam curve upwards ( U shape) , then it has positive...

Hello guys, I am doing some basic design work and can't remember how offset torques work. I am doing the sum of the torques should be equal to 0 in order to find the tipping point around either of the wheels. My problem is with the 1000N applied at to top taking the pivot point around the...

Homework Statement Please see attached picture Homework Equations principal of moments The Attempt at a Solution part a) is fine. For part b, I would Normally take moments about C. The force acting on BC at B must be the tension in AB. The geometry of the triangle gives and angle of 53.1 to...

Homework Statement A given pulley has a radius of 20 cm and moment of inertia 0.2 kgm2. The string going over it is attached to a vertical spring of spring constant 50 N/m on one end and a 1 kg mass on the other end. The system is released from rest with the spring at natural length. Find the...

Homework Statement A gardener pulls a roller of mass 85 kg over a step. The roller has a radius of 0.25 m. The handle is attached to an axle through the centre of the roller at an angle of 45 degrees to the horizontal. Here's a link to the diagram below, it's figure 1 and 2 on question 18...

Homework Statement We are given a diagram to which we need to make measurements of. There is a line Y which is 9.5cm long. At one end, point X, is a force of 6,500N going perpendicular to the line; at the other end is point J, which the line continues for another 4.5cm to point P which is the...

Homework Statement Determine the moment of inertia of a rigid body on the picture: The radius of the inner cylinder is R and the outer is 2R. Homework Equations 3. The Attempt at a Solution [/B] I thought of subtracting the big cylinder inertia from the small and adding the hanging body and...

Homework Statement Find the period of small oscillation of this system. Homework Equations 3. The Attempt at a Solution [/B] I understand the concept of moment of inertia but can't comprehend the first equaion here. The other two i get and they are moments of inertia of other two bodies...

Homework Statement A uniform ladder 5m long and of mass 40kg rests with its upper end against a smooth vertical wall and with its lower end 3m from the wall on rough ground. Find the magnitude and direction of the force exerted at the bottom of the ladder. (G=9.81ms^-2) Homework Equations...

Homework Statement Hi, I have the probabilty density: ##p_{n}=(1-p)^{n}p , n=0,1,2... ## and I am asked to find the characteristic function: ##p(k)= <e^{ikn}> ## and then use this to determine the mean and variance of the distribution. Homework Equations [/B] I have the general expression...

I have calculated characteristic function of normal distribution f_{X}(k)=e^{(ika-\frac{\sigma ^{2}k^{2}}{2})} and now I would like to find the moments, so I know that you could expand characteristic function by Taylor series f_{X}(k)=exp(1+\frac{1}{1!}(ika -...

Homework Statement I need to sum the moments on a and b but when i sum them at b the number I get doesn't work when I check and sum them at a. Homework EquationsThe Attempt at a Solution

Homework Statement Need help at "Forming an equation based on the fact that all the vertical forces must be in equilibrium". I'm to calculate the reactions at the supports A and B by doing: (i) Forming an equation based on the fact that all the vertical forces must be in equilibrium (ii)...

Homework Statement Find the force of attraction between 2 magnetic dipoles a distance r apart. Both dipoles point to the right. Homework EquationsThe Attempt at a Solution All I need help with is figuring out how to determine if the force is attractive or repulsive between the 2 dipole...

Hi, this is my first forum post - sorry if I'm in the wrong place, or I've done something wrong! Homework Statement Here goes: There is a beam of 0.5m length hinged to a wall at a right angle with 200N mass at the end of the beam. This is supported by a wire T at angle 30°. The question asks...