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Questions tagged [statics]

Statics is branch of engineering concerned with the analysis of forces and moments on physical systems in static equilibrium.

When a system is in static equilibrium it experiences no acceleration (the net force on the system is zero). Questions regarding statics problems should be asked here.

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Why are screw holes in most of the door hinges in zigzag orientation?

What advantage does it provide? Explaining with a figure would be helpful. I tried to draw a free body diagram and equated the sum of force and moments to zero, but still was not able to find out.
Qwerty
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How should I position two shelf supports for the best distribution of load?

I'd like to mount a shelf on the wall. I have two shelf supports to do so, like this: Relative to the shelf, where do I place the (blue) supports to achieve the best distribution of load?
Nico Schlömer
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How to calculate lever force when lever has uniformed distributed load?

We have a simple class 1 lever: $$\begin {array}{c} \text {5,000 kg} \\ \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \,…
Van
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Why does a gear have extra holes?

In a gear you normally have a center hole for the shaft to be put into. Why do some gears have holes surrounding that center hole? Is it for weight reasons? Does it add stability? Is it so you can add special parts?
Mat NX
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How do I calculate the forces on a desk and its legs?

I have a design for a desk, and I'd like to not just guess at how strong it'll be, but I can't find an explanation on how to figure out all the forces involved that doesn't assume I already know a lot about engineering already. So, if I were to…
mordac
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Where did I go wrong conceptually when attempting to calculate the maximum force on a truss at a given joint?

In the problem statement below, the question states to find the maximum load $\vec{P}$ that the truss can support. My method of approach was: Draw a FBD for the entire structure. Generally I would identify all external forces, however for this…
Hunter
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How to deal with a point force acting right on the hinge of a beam?

I have been attempting to solve a question where there is a point force acting on the hinge of a beam. Here is the problem: I am not sure how to deal with the 2 kN point force at $C$ ($C$ and $E$ are the hinges). If I split the beam into three…
saldtch
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Incompressible 2D pressure-driven flow: for Navier-Stokes equations in nondimensional form, how should I express pressure boundary conditions?

*I have updated this question. I'm using two codes for modeling incompressible, two-dimensional flow out of a tank. My fluid dynamics experience is pretty basic; I'm using the codes to understand a chemical process. The codes haven't been used…
Ant
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Moment equation from dynamics differs with equations from physics & statics. Where did I go wrong?

In my dynamics class, we're being asked to solve the following problem: My Attempt: Since I'm given the initial velocity, final velocity, and distance, I solved for the acceleration of the plane using kinematics: $a = \frac{v_f^2 - v_i^2}{2d} =…
Chris Forsyth
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What is the benefit of additional planetary gears?

A planetary gear is a gear that rotates not around an axle but around another gear known as a sun gear, or star gear. I have designed prototype systems in the past that used a single planetary gear rotating around a rotating gear. However since then…
Sam Weston
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Calculating moment of inertia for a hollow discontinuous circle?

This is a pretty simple problem, but I'm just not sure how to go about it. I want to find the moment of inertia of a discontinuous hollow circle. But since the shape is so irregular, I'm not sure how to go about solving for it. I've posted the shape…
tempestwing0101
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Height limits of brick and mortar tower?

What are the factors limiting the height of a "tower" made of typical fired brick and mortar? By "tower", I mean a structure whos point is to be tall, and can support a human standing on or near its top. I'm interested in the self-supporting…
Olin Lathrop
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Calculate effort to raise hinged lever with distributed load

My father-in-law would like to install a hinged stair system in his garage that allows him comfortable access to his attic space. He wants the stairs to swing up flush with the ceiling when not in use, and then to easily swing down when he needs it,…
alfreema
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Differential equation of the vertical displacement of a cable

Given a cable (totally flexible) fixed at both ends, subjected to a vertical force $f(x)$ in his plane, with variable area $A(x)$, and variable elasticity $E(x)$ I want to find the differential equation of the vertical displacement $y(x)$ in his…
Msegade
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Mathematical representation of hinge and pin connection

Following on from this answer, I am reading about the difference between hinge and pin connections here, and I don't quite understand about it. I think I would need to see the mathematical representation ( the boundary condition) involving pin and…
Graviton
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