Questions tagged [statics]
Statics is branch of engineering concerned with the analysis of forces and moments on physical systems in static equilibrium.
228
questions
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1answer
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Find Acceleration Of A Buoyancy Force Of A Balloon In U.S. Customary Units (1-49E)
The problem in my text (Thermodynamics An Engineering Approach, Cengel & Boles, 2nd Ed.) is stated as follows:
Balloons are often filled with helium gas because it weighs only about one-seventh ...
4
votes
2answers
958 views
Statics and Structural Analysis: Determinacy in beams/frames
I have a question about the methods to decide whether a beam/frame is determinate or indeterminate. Typically you can count the number of reaction forces and compare them to the number of elements to ...
0
votes
1answer
123 views
What engineering topic builds upon the concepts of basic statics?
I'm interested in learning what I might call "advanced statics" but am not sure what concepts this would include in engineering parlance.
Would it actually be called "matrix structural analysis"?
2
votes
2answers
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Best angle and length for a diagonal wood support for a pull-up bar
I want to construct a freestanding pull-up bar like the one described here.
But I was wondering what would be the best angle for a diagonal support considering that the things I care are:
That it ...
7
votes
1answer
2k views
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 ...
2
votes
1answer
1k views
Drawing Bending Moment Diagrams
How do I know when to use an upward or a downward curve when I'm drawing a bending moment diagram for a uniformly-distributed load (UDL) and what's the most reliable way of identifying the maximum ...
2
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1answer
2k views
How to calculate strain from maximum bending moment and stress?
How can I calculate the strain in a simply supported beam from having the maximum bending moment (25kNm) and the maximum bending stress (45MPa)?
1
vote
1answer
665 views
Frame/truss problem with sliding joint
I'm supposed to be finding the reaction forces first but from the FBD of the entire truss where am I supposed to start. If I take the moment at A then I get 3 unknowns at Bx Dy and Dx. If I get the ...
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vote
1answer
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Loaded Truss problem
Hi, I'm having some problems with this truss question that I have in my homework. So far this is my solutions.
I worked out my solutions to the reaction forces but don't know if they're correct.
The ...
3
votes
2answers
4k views
How to calculate the forces on members of a frame, due to a distributed pressure load?
I am trying to calculate the force sustained on the three labelled members of this frame (Members 1, 2 & 3). The frame will experience a uniform pressure of 1000 kPa in the area enclosed by the ...
1
vote
1answer
55 views
The Equation of a buckled card
When a rectangular piece of plastic (say a credit card) experiences an increasing compression force, the plastic eventually buckles. Is it possible to find the equation of the plastic's cross section ...
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2answers
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Why is there a moment at the cross section end when you cut a body?
I just started mechanics of materials, and it seems that my knowledge from statics has gotten rusty over the summer. But there was a new concept introduced in the first example problem today.
There ...
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1answer
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Calculating automotive suspension wishbone loads by considering the structure as a 3D Truss
I am trying to calculate the loads in the suspension components of a typical car double wishbone setup. I have found a thread on the www.fsae.com forum, which seems to be exactly the kind of thing I ...
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1answer
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How to analyze the free body diagram of a pair of scissors? [closed]
Is this how it works?
The fingers generate moment.
The load generates moment.
Finger moment > load moment, so the load is cut.
How do I use an equation to identify the most vulnerable point of the ...
10
votes
2answers
31k views
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 ...
3
votes
1answer
4k views
Drawing the shear and bending moment diagram of a 2D rigid frame [closed]
I am taking a civil engineering course that we are constantly asked to tackle questions that are not really covered in the course. I have been looking for suitable reference materials but with no ...
2
votes
3answers
829 views
How to describe the rotation of opposite ends of a body due to an applied moment
Summary
A short way to phrase this question is:
Shear describes the translation of one part of a body relative to another given an applied force. What is the equivalent rotational term? That is,
...
4
votes
0answers
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Calculating a pull force between two pieces of plastic
I have an HDPE pin, 2 mm high, 2 mm diameter, that I impress into a flat plaque of hot HDPE. It is not hot enough to melt the pin, but still hot enough that the material will shrink 4% in 24 hours.
...
4
votes
1answer
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What angle - for a strut - provides the greatest vertical strength/support for a cantilever?
I want to affix a cantilever to wall. I will support the other end of the cantilever with a strut made of wood, that attaches to some point on the wall below the cantilever, as shown in this sketch (...
4
votes
4answers
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How to calculate a tripod table's stability?
I have designed a circular, 800 mm (31.5") diameter tripod table. The top is made of stone and weighs 40 kg (88 lbs). The height of the table is 750 mm (29.5"). There is a central column with tripod ...
5
votes
3answers
3k views
Does the length of a beam change upon deflection?
I have made a Python program in which I have computed the deflection of a beam.
I am plotting the deflected beam and am now asked to show the length of the beam.
If the beam is not deflected, it is ...
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vote
2answers
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Beam with constant load distribution on three supports - force distribution to supports
I have following example (the question is at the bottom):
The load distribution $q$ is constant. I add condition of zero bend in center of the beam, $w_B = 0$, and the assumption $F_{RA} = F_{RC}$. ...
4
votes
2answers
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How to solve an overconstrained static free body diagram?
How does Force Effect https://forceeffect.autodesk.com do it? Given a 10m long bar angled as the hypotenuse of a 3, 4, 5 triangle with an xy pin constraint a (0,0), another xy constraint at (4,3), ...
3
votes
1answer
564 views
How do I determine the reactions at the base of a tethered T-frame?
I received a tricky bonus question today in my engineering class:
I've begun by equating all moments and forces to zero, about an arbitrary point, which I labeled at $C$. Finally, I attempted to ...
12
votes
5answers
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How to calculate lever force when lever has uniformed distributed load?
We have a simple class 1 lever:
$$\begin {array}{c}
\text {5,000 kg} \\
\downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \...
3
votes
1answer
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Is the Qmax of an T-Beam equal if calculated both above and below the neutral plane?
I was doing a question involving a T-Beam question wrong since I was selecting the wrong area to use for $Q_{max}$ when trying to maximise the shear stress.
$$\large{\tau}= \frac{VQ}{It}$$
A friend ...
7
votes
1answer
4k views
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 ...
12
votes
4answers
6k views
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 ...
