Questions tagged [statics]

Analysis of a system of bodies where all forces are in balance and there is no motion relative to a chosen reference frame.

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Weight Needed to keep wall from falling over [closed]

any help would be appreciated. I am trying to figure out how to calculate how much weight is needed to secure a pedestal wall/ display wall. The wall will hold or have objects hanging off the front ...
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Biomechanics question related to force [closed]

A person working at a drafting board may hold her head as shown in Figure, requiring muscle action to support the head. The three major acting forces are shown. Calculate the direction and magnitude ...
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Moment on a rectangular concrete slab

Here is a picture from my engineering textbook. It describes a concrete slab being subjected to normal force $P$ and a certain moment. The moment is expressed by the normal load $P$ affecting at some ...
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1answer
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Suspicious of Khan Academy's answer for a simple tension on a clothesline question [closed]

This is the question: 3 kg of wet clothes are hung on the middle of a clothesline with posts 6ft apart. The clothesline sags down by 3 feet. What is the total tension upon the clothesline? They give ...
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4answers
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Does a planar object balance on a unique point?

Consider a horizontal planar convex 2D object (say lying on x-y plane) with uniform density. Under constant gravitational force (say in -z direction), does it always balance on a unique point lying ...
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What does the vertical plane which passes through the the line of the greatest slope of an inclined plane represent?

I encountered a problem while solving a question about friction force regarding static bodies The question is as follows, "A body of weight $W$ is placed on a rough plane inclined to the ...
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Calculate Tipping Force of Table [closed]

How do you calculate the force it would take to push over/lean on a table for that table to tip. The table top is 144" X 40" and weighs 281 lbs. The table is supported by (4) table bases ...
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Distribution of weight among massless strings hanging a rod of uniform density

Let the mass of a rod of uniform density be $W$ and its length be $l$. Several massless strings have been used to hang the rod at positions $x_1, x_2, ..., x_n$ where $0 \leq x_r \leq l$. Find ...
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Why is the normal force of a traffic light pole merely exerted by the right bolt?

In reference to a recent statics problem, please see inserted picture for the correct situation below, it was required to find the magnitude of force ($F_3$), exerted by the leftmost bolt on the ...
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2answers
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Friction on a rod resting against a rough horizontal rail? [closed]

In which direction does friction act on a rod leaning on a rough horizontal rail, where the normal force is perpendicular to the rod and the rod has its bottom end on a smooth horizontal floor with ...
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Conditions for equilibrium on a hexagonal pencil [closed]

A hexagonal pencil lies on a slope with inclination angle α; the angle between the pencil’s axis and the line of intersection of the slope and the horizontal is φ. Under what condition will the pencil ...
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1answer
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Mechanical Advantage of Static Double Pulleys

For a set of two double pulleys, the force acting on each should be equal to the tension in the rope times the number of ropes connected to the individual pulley if I understand correctly. In this ...
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Strength of wall regarding a system of hanging mass

When we assume that mass m is directly at the center of L, and $\alpha$ is the angle between the rope and the horizontal, I am able to show that for equilibrium, $$\sin{\alpha}=\frac{m}{2M}$$ There is ...
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Shortcut to a problem based on toppling using D'Alemberts Principle [duplicate]

I found this question on this very site and was curious on how to solve it using D'Alembert's Principle Here's the link to OP(link) .I already know how to do it by balancing the torque about toppling ...
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An equation related to lever

To balance a lever, as we know, fulfills $f_1l_1=f_2l_2$, what is the condition that fulfills both $f_1l_1=f_2l_2$ and $f_1+l_1=f_2+l_2$?
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Horizontal tension in hanging rope with mass [closed]

If we have a hanging rope with mass so that it forms a catenary, from what I have read, the horizontal tension in the rope remains constant. I also have seen that the equation of a catenary depends on ...
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Does an elastic massy hanging chain take the shape of a parabola?

This is a problem in "Differential Equations: A Modern Approach with Wavelets" by Krantz: If the length of any small portion of an elastic cable of uniform density is proportional to the ...
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1answer
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Geometry of deformation of Axial members connected to a rotating rigid element

On axial members connected to a rotating rigid element, we have the following relationship $$\frac{-\delta_1}{a}=\frac{\delta_2}{b},$$ which is based on the concept of similar triangles. In the ...
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Tension in Common Catenary

I was reading the intrinsic equation of common catenary , where the author assumes tension in the catenary and proceeds. Why does a freely hanging rope with uniform mass per unit length has tension ? ...
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1answer
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Position of resultant of two like parallel forces

I am solving Statics and stuck in middle of a trivial understanding. Let us say we have two like parallel forces acting on a rigid body . Force P has point of application as A and Force Q has point of ...
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2answers
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Expression for force of gravity on an arbitrary curve with endpoints fixed

Consider the following problem: A frictionless tube lies in the vertical plane and is in the shape of a function that has its endpoints at the same height but is otherwise arbitrary. A chain with ...
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3answers
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Can you calculate the force of chair legs on floor?

I have kinda formalistic question. Eg. we have normal symmetric chair with 4 legs, and mass $M$. Can we calculate forces of chair legs on floor surface $F_1,F_2,F_3,F_4$ with only this data and why ...
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Question on statics

Consider a uniform beam that is supported by 3 pivots that are the same distance from each other (shown below). What will the normal force exerted by each pivot be? The situation seemed rather ...
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1answer
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Static equilibrium problem [closed]

I am designing a balanced-arm lamp structure for a robotics project and I obviously want the lamp to stay on its base without falling when the arm is extended. For that, I applied the conditions for ...
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3answers
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Measurement of force (statics) [closed]

body 1 and 2 are pulling the balance by 20 N what does the balance read? same question but without 2. for 1st question I thought the balance will read zero force because they are two opposite forces ...
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How come at a certain joint a truss is a zero force member and at another is isn't?

I have a slight confusion regarding zero force members. I'm analyzing a structure and I started at joint E and found that truss GE has a force of 8.4 [kN]. However, if I analyzed it at joint G, I can ...
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Resolution of forces (vector components) to find the resultant force [closed]

I'm a CAIE AS-Level student and I'm having a bit of problem with a physics question. It goes like this, An object X rests on a smooth horizontal surface. Two horizontal forces act on X as shown in ...
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Is it possible to create negative ions without ionization?

I read that the air purifiers that can create negative ions also increase ionization, in theory is it possible to create a negative charge/ negative ions without creation ionization similar to ...
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Hooke’s Law and Energy

I have a quite a simple question that is escaping me right now. The work done on any body is just the net force multiplied by the distance the force acts on it for. For example: the work being done on ...
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How to find the loads of the four posts of a deck?

For a square deck of length 1 and neglectable weight, if it has to hold a heavy weight of mass M at (x, y), what is the support force of the four posts at the corner? The forces are $F_{00}$, $F_{10}$...
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1answer
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Using preload to resist bending moment on an unfixed cantilever beam

I have a cantilever beam that is resting against a wall (not fixed) and will not slide (strictly looking at bending moments). The beam of length = 0.3m is under a distributed load of 4000N and a ...
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How do I calculate the effort force exerted by my hands while holding a high plank? [closed]

This high plank is an example of a 2nd class lever. The fulcrum is at the feet, the load is at the centre of gravity of the body, and the effort is at the hands. If I know: My weight (the load force)....
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Pulling force required to get stationary vehicle moving

Background There are many examples from humans pulling heavy vehicles, ranging from trucks to airliners. When researching the physics behind this, most results pointed to the reduced rolling ...
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The Leaning Tower of Pisa [closed]

Can we calculate the time when the Tower will lean to the extreme point that its center of mass will be out of its balance...?
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How do we account for the non-net accelerations for forces in static systems?

I've googled the heck out this (as a non-physicist) and found a ton of similar questions answered but did not find anything that made the light bulb go on. I don't think I'm a crank, so here it goes. ...
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What is the physics explanation for why an object with a larger base is more “stable” or and more able to “balance”?

What is the physics explanation for why an object with a larger base is more "stable" or more able to "balance"? For example - two pyramids, one on its tip (less stable) VS one on ...
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1answer
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Water column's pressure canceling out problem and it's microscopic point of view

If you see my horrible reference picture, you will see that the U shaped tube is placed inside the field where gravitational force exist. And the bottom of the tube is opened, tube is filled with ...
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5answers
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Does putting a thin metal plate beneath a heavy object reduce the pressure it would have applied without it

My dad bought an earthen pot and he kept it on our glass table. Worried that the glass could break on filling the pot with water. I kept a metal plate beneath it. At first, it seemed like a good idea ,...
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How do we decide which tension forces get included in the force- and torque-balance equations?

Consider a static equilibrium problem like the following: The uniform boom shown below weighs 700 N, and the object hanging from its right end weighs 400 N. The boom is supported by a light cable and ...
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3answers
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Two standing sticks with a hinge, seems to lead to a paradox?

I have kind of a paradoxal question about two sticks connected through a hinge that rest on a frictionless floor at the bottom and frictionless walls on each side at the top. What are the forces in ...
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1answer
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Why the dust on the wing cannot be cleaned by air flow? [duplicate]

I recently saw that the dust on the airplane's wings are frequently cleaned by some human workers (generally after every trip, workers clean the fine dust on wing's surface by hands). But I have a ...
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How to prove that objects have nonzero torque when center of gravity is outside area of support?

I’ve been learning the concepts of static equilibrium and the book I’m using is providing examples of objects that are unstable when their center of gravity is outside the area of support. For example,...
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1answer
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What forces are applied to the wall when some thing like a cooler is attached to it? what makes the normal force? [closed]

what force throw to the wall is applied in this situation? what force does this wood is importing to the wall that makes the normal force?
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1answer
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Biomechanics statics of an push-up [closed]

So I am really struggling with a statics problem about calculating forces and torques of an exercise. So I need to calculate the forces acting on the feet and hands, as well as the torques, for 2 ...
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3answers
46 views

How to find the equilibrium point of a system that is bowl shaped and a mass inside the bowl with given potential energy function?

Question: $z=U(x, y)=ax^2+by^2, (a,b \in R^+)$ is the potential energy function of the system. How to find the equilibrium point of this system? We have to find the equilibrium point of this system ...
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Intuition behind First moment of area and link to centroids

I essentially have the same question, however only concerning the First moment, as this user ,however none of the answers satisfy my questions. I understand that we are trying to get a sense of the ...
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1answer
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Forces in statically indeterminate system

I am a bit puzzled about the meaning of statically indeterminate in particular in terms of force distribution. The following system is clearly statically indeterminate: There are four reaction forces ...
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1answer
92 views

Deflection of L bracket [closed]

I want to calculate the deflection for an L bracket like https://imgur.com/a/0PabX0T to determine how thick I will need to make the steel for a workshop shelf. I have done the calculation using the ...
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1answer
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How can I calculate the coordinates of segments that form a hanging chain?

I'm trying to get a chain physics model with segments. I'm feeling rather stupid, but how can I calculate which is the new position of each dot when the chain moves its ends? expressed in another ...
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2answers
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A problem about moment (torque ) [closed]

Everybody knows that moment of a force increases with distance. However, there is a problem about it that makes me confused these days: Let's take a look at this picture due to the formula M = F.d, ...

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