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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27 views

Question please, [on hold]

Why the resultant force is less than the applied force?
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1answer
21 views

Stuck on certain types of static equilibrium problems [closed]

I'm not looking for a direct answer, more like something that can get me started. A lot of the other problems like this were easier, but I'm just lost. This concept seems really difficult to me in ...
1
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2answers
32 views

Why moment equilibrium must be calculated around the center in this problem?

Consider this problem, which ask for the value of the two normal forces (friction is negligible). Easy, right? You calculate the moments around G, the center of mass, and equate them to 0 (the ...
0
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1answer
28 views

Rope tension definition

What is the exact definition of the tension of a rope? Here http://web.mit.edu/8.01t/www/materials/modules/chapter08.pdf the following definition is given The tension $T(x)$ in a rope at a ...
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1answer
21 views

I need help with determining angles after shifting of axis in Free Body Diagrams

I can't figure out by which property of the triangle the angles in shifted axis are also 30 degrees. Vertical angle theorom doesn't work. I drew it again and again. If someone could draw me a ...
1
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1answer
26 views

Stuck on a static equilibrium problem [closed]

This is the problem: "The figure below shows a 25-foot sailboat. The mast is a uniform 119-kg pole that is supported on the deck and held fore and aft by wires as shown. The tension in the forestay ...
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1answer
35 views

How would you get the velocity in this problem? (and what did I do wrong) [closed]

This problem is supposed to be solved by using the conservation of energy but I do not really know how to solve it that way.
1
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1answer
43 views

What component of the payload appears on the cross member? [closed]

I have a set of DIY steps; I've modelled it as the steps themselves "s", a short vertical support "a", a long vertical support "b" and a cross-member "c". Here's a picture: Just to be sure I ...
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4answers
83 views

Draw the Free Body Diagram

Question: Draw the Reaction Force at point P. My Attempt and Reasoning: Since the Reaction or the Normal Force is normal to the surface the solution according to me should be- However, the ...
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1answer
32 views

Basic tension and equilibrium confusion

The following is what I did: $$Fsin\theta = 60 => F = 93 N$$ $$Fcos\theta = 40 => F = 52 N$$ Why do I get different results? Does this mean the object isn't in equilibrium? How can I ...
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0answers
35 views

Axial loaded bars problem

I completely disagree with the following calculations: Based on my understanding, there is no force either internal or external applied to the Green bar, so it should be 0N. The reaction (internal) ...
3
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1answer
127 views

Why curvatures relieve stress?

Per example, we can stop a crack in a steel plate by drilling a hole at the end of it. Or we all know the famous example of popular science that airplane windows are round for the same reasons. Why ...
1
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2answers
48 views

Mass required to prevent sign falling over with a set wind load - activity stations for disabled children

I'm currently working on my thesis and I'm stuck on a question. I'm designing activity stations for disabled children to be used for equine therapy. The stand is 9ft tall and I've calculated the the ...
2
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1answer
102 views

The Physics Behind the American Death Triangle [closed]

I've heard a lot about the American Death Triangle and how it is awful for belaying. The Death Triangle is set up as such: you have two anchor points with a single rope or line running through both ...
1
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1answer
74 views

Calculating force with two fulcrums and many forces [closed]

I may not be wording the question the right way. I have a lever. About 2/3 the way back there is a pivot point. We'll call this B On the very front (end of the lever) there is a block that the lever ...
1
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3answers
411 views

Do supports exert torque?

I think I'm missing something about torques. Do supports exert torques? Consider these two situations I'm confused about. A rod is attached in to a wall so that it cannot rotate. Since weight ...
0
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0answers
32 views

Mechanics (Static Forces) [closed]

If you don't mind anyone could help me in this mechanics homework its static question In number one i got T-cd=500 and T-ca=230.9 and T-bc=184.5 in number two i got stuck in finding the forces ...
0
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0answers
7 views

Toledo Scale - Show How Distance from Weight to Axis of Rotation Varies with Load

I am trying to solve the problem under from Hartog's Mechanics, specifically, part $b$. Intuitively, as mentioned here, by halving the load $P$, $l_1$ will also be halved. However, I would like to be ...
2
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1answer
29 views

What are the clicking sounds when static electricity occurs?

Sometimes, when there's static electricity, soft clicking sounds can be heard. This may happen when two fabrics are rubbed or when you get a static shock. What exactly causes this sounds?
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0answers
81 views

What way did this person solve the problem? [closed]

Im curious, I have no idea how they solved the problem to get from the unitary vector to the Moment/Tension. How did they managed to get it so reduced? What steps did they perform in the blue part?
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1answer
32 views

Maximum Load of a Crane before Car will Tip

Imagine a car with a crane. In scenario 1, the tension on the crane cable by the load points straight down, ie, perpendicular to the ground. In scenario 2, the tension on the crane cable by the ...
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0answers
23 views

Interpreting force components in statics problems involving inclined planes or similar

I'm having troubles to understand how to interpret the components of forces on inclined plane in quite complicated situations. I will make an example of one of the cases where I get confused. ...
0
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2answers
48 views

Angles in a static equilibrium

I have three masses (Fα, Fβ & Fg) with 2 pulleys, and a wind variable which is in static equilibrium. I have already calculated the appropriate forces for the 3 masses by multiplying it with ...
1
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1answer
58 views

Homework Question: Moments [closed]

Can someone please explain this question? My work: If we take B to be the pivot then as B gets closer to mg the torque due to mg gets smaller, but I don't really see how this affects the force F (I ...
0
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1answer
52 views

Laws and Intuition for physical problems

So I've been reading the book 'Feynman: Tips on Physics' recently and in chapter 2 (the book is available for free online) he works out the answer for this problem using his intuition rather than ...
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1answer
217 views

Determine resultant couple moment by summing moments

The question states: Determine the resultant couple moment by (a) summing moments about point $O$ and (b) summing the moments about point $A$. I used scalar analysis for solving this ...
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1answer
55 views

Converting loads on horizontal surfaces to inclined surfaces

A textbook on design of wood structures makes the following argument: We have a flat roof snow load $$S_1 = 61.6 \frac{lb}{ft^2}$$. The idea is to convert it to an equivalent sloped roof snow load ...
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3answers
83 views

Tension in rods (basics)

I have a problem understanding these basics. What is the tension in the ground rod due to the forces exerted by the slanted rods? Please feel free to correct me at any point. Rods are idealized ...
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2answers
40 views

Static Equilibrium [closed]

A 3 Newton force and a 4 Newton force are acting concurrently on a point. Which force could not produce equilibrium with these two forces? 1N 7N 9N 4N I'm confused. The book I'm looking at says ...
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0answers
26 views

$16~\rm N/mm^2$ flexural strength

This question more relates to construction and architecture but I am sure it will not be the problem to ask and get a good answer here. If we have declared flexural strength of concrete of 16 N/mm2, ...
2
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1answer
145 views

Newton's Third Law As Discussed in Den Hartog's Mechanics

A question, but some preliminaries in order to avoid answers involving concepts not yet introduced in the text I'm reading--Den Hartog's Mechanics. Near the very beginning of his book, Den Hartog ...
0
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1answer
73 views

Seesaw Physics - Shipping Container House Problem

I'm currently building a house using shipping containers. One of the containers is in a cantilever position, sticking out from the base concrete structure like this: ...
0
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1answer
48 views

Not sure how to solve a problem from online course [closed]

I'm not sure how to approach this problem. I don't know the magnitude of F1 or F2 and I'm not sure how to get it from F. Any help would be appreciated.
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2answers
82 views

Why don't barbells tip over when a 45 is placed on one side?

A standard barbell is 45 pounds, as is the heaviest weight available in most gyms. When a weight is placed on the side of a barbell, some of the barbell is to the "outside" of the weight, like so, so ...
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0answers
44 views

Tension on wire holding open door, using moments about a hinge? [closed]

Using moments about the hinge, what is the tension in the wire holding the door open? The wire is horizontal. The door is 5m. See diagram: The door is at tan inv (3/4) : 36.9 deg to the ...
0
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1answer
25 views

When an object hangs from a Rigid rod is the force of the weight located in the center of the sign?

From the rope that supports the sign (assuming the mass is distributed evenly). If the length of the sign is, $L$ can I model it so that the weight is concentrated at $\frac{L}{2}$ Therefore, the ...
2
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0answers
36 views

Applied forces on a bridge [closed]

What are the forces that acted on the 6 types of bridges? Beam, Truss, Cantilever, Arch, Suspension, and Cable-Stay? What formulas do you use to get the forces? I'm curious since there is ...
2
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2answers
106 views

how does one divide stress in such a bridge? [closed]

I want to build a spaghetti bridge like this: I have two spaghetti types: T-type (designed to tolerate tension) and C-type (designed to tolerate compression). A mass $m$ is hanging from the point ...
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2answers
47 views

Determine the point at which moment vector is zero on a 3D body

I have information about total force and moment on a body for three points, whose coordinates I know. From this information I would like to determine the point at which moment would be zero. ...
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1answer
43 views

Difference of water pressure

We know that $P = \rho gh$, so is it true that water pressure at 2nd floor will be higher than water pressure at 9th floor of a 12 story building?
-1
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1answer
107 views

Confusion about two-force members

This is my first question here so I hope I get warmly welcomed by answers that would resolve this perplexion :-) This is a statics problem from Hibbeler's Mechanics for Engineers: Statics (13th ...
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1answer
21 views

Transferable force

If I for example have two rectangular pieces of steel that are both W=40mm, L=1000mm, H= 40mm and are both completely ridged. One piece of steel is resting on top of the other piece of steel, if I ...
1
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0answers
38 views

Roberval Balance [closed]

Is there any mathematical/mechanical article that explains in detail why the Roberval balance is taken place? I generally observed that the classical mechanisms are not analysed in detail, even in ...
0
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2answers
71 views

Equilibrium equations

You have one horizontal beam. Its left point is attached to a free pivot at the vertical wall. Its right point is suspended by a rope from the ceiling. Nothing is moved. So $\sum F=0$ and $\sum M=0$. ...
2
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2answers
49 views

I'm building a bubble pane. What can I do to reduce static pressure? [closed]

I'm building a bubble pane, just for decoration in my home, using some patio door glass panes and an aquarium air pump. Soon into my testing, I learned what static pressure is. When I fill it up, even ...
0
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1answer
23 views

Distortion of non-circular cross sections upon torsion

True or false? Non-circular cross sections can be non-planar when torsion is applied. This was on a quiz today and I wasn't sure of the answer. I guessed true by intuition, but does anyone have a ...
0
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1answer
55 views

push up weight distribution [closed]

I'm about 84 Kg, in push up position (hands on the scales) the scales show about 54 Kg. Can anyone explain briefly the physics of the weight distribution? (I did high school physics decades ago - ...
1
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3answers
400 views

How is normal force distributed along the surface of contact?

Help me settle this argument. A mass $m$ is placed on a thin diving board. The base of the diving board has mass $M>>m$. Does the board tip over? I drew the following FBD and concluded there ...
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1answer
68 views

Lever Mechanical Advantage

In the attached image the force output of the plank is calculated to be the work done (FDf) divided by the height the block rises (Dw). So the force the plank applies on the block is (FDf)/(Dw). But ...