Questions tagged [geometry]

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How do I calculate the angle of the handrail transition if both need to be set at 33 degrees around a 90 degree corner?

How do I calculate the angle of the handrail transition if both need to be set at 33 degrees around a 90 degree corner?
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Piston that produces equal amounts of swing in a lever?

I am attempting to figure out an equation I've found for designing part of Walschaerts Valve Gear. The specific implementation isn't relevant here, because it's the math I'm after, but this is the ...
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Is there a geometry that meshes exactly with a rope?

I'm in a use case where the outer surface is a gear driven by a motor (that's the easy part) and the inner surface meshes with a metallic (iron) rope. When the part rotates, I want the motor and ...
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At what steepness does a vehicle start rolling?

At what exact gradient does a typical vehicle in the following classes start to roll away when the brakes are released and the transmission is in neutral? I'm trying to design a super-safe parking lot/...
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Maximum Slope of Truck Parking Lot

What is the maximum grade/gradient allowed for non-temporary (overnight or longer) parking/vehicle storage areas in parking lots for heavy-duty vehicles such as semi-trucks and buses? All I could find ...
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3 answers
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Figuring out Geometry for Kreg 720

I'm making pocket holes to connect wood together with a jig, the Kreg 720. The 720 works by moving at an angle (which I'm trying to measure) to ensure the hole is drilled higher on thicker pieces. The ...
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Help with engineering graphics

Please redirect me if this is the wrong place to post this, however I've been having issues with something for engineering graphics classes and need some help I'm supposed to draw two intersecting ...
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5 answers
154 views

How do I calculate surface area of dashboard through integration?

How can I calculate surface area of dashboard through integration. I traced the surface using pencil. I can calculate rough area but I want to calculate actual area through integration. The vertical ...
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1 answer
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Inside/outside test of any point on 2D plane?

Suppose I have one plane $Ax+By+Cz+D=0.$ I want to test $(x, y, z)$ is inside of this plane or outside. My attempt:1 Then draw normal N on that plane which point away from the observer Image1. If $Ax+...
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3 answers
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How to calculate perimeter of spur gear?

I'm in need of some gears, but having them made by a machinist is very expensive so I'm planning to have them laser cut. Loads are reasonably low for any grade of steel, so I'm hoping it should be ...
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2 votes
1 answer
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To stop or to go around?

Let us we are moving in a car. There is a wall in front of us, we need to decide can we go around it or not. It is known that width of the wall is $w$ and our speed is $v = const$. What is a simple ...
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Why is the area of upstream face of control volume a stated?

I cannot seem to visualise why the area of the upstream face of control volume is 2pir∂r, can someone pls clarify on why is this the case?
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Does anybody know where this calculation for the mass moment of inertia for an eighth of a circle comes from?

These attached photos describe flaps which are a portion of a circle and equations are attached as the mass moment of inertia, but there are no descriptions. I am using this for part of my research, ...
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horizontal angle of view based on distance from window [closed]

I am looking for an equation to provide me the angle of view based on a distance from a window. I'm only interested in the horizontal not the vertical.
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2 answers
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How to calculate miter angles for an angled stretcher

See the image below: When I lay this out in Fusion, I can get the angles but I can't figure out how to calculate it mathematically. The goal is to have the angled stretcher fully contact the upper 45&...
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4 votes
1 answer
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How to trace a square with a reuleaux triangle

I am trying to trace a square (with rounded corners) using a reuleaux triangle and a single (circular rotation) motor. I've seen many animations (example) of this but do not understand how to make it. ...
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Is a pyramid considered axisymmetric? Why so?

I read a source, I will not reference the source on this platform. They stated a pyramid is axisymmetric. Can you explain why if yes?
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When calculating a car's suspension caster, after turning the steering wheel 20 degrees, why multiply by 1.5?

To calculate caster of one side of a vehicle, the steering wheel is turned 20 degrees to the left, and the camber is obtained; this represents the 'in' value of the front right tire. Then the steering ...
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2 answers
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How to calculate meters per pixel for a given camera?

I am stuck on this problem for a while: I have a square-shaped camera, with: 1000 pixels on vertical side 1000 pixels on horizontal side I want to know the number of meters per pixel depending of ...
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How could I get the coordinates of the circumscribed circle giving the 3 points coords?

I have the coordinates of 3 points thrgouh which, a circle should pass . Having the coordinates of the points in 3D, how could I have the coordinates of the center of circumscribed circle ? also : if ...
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Program for creating a cylinder given its axis, center and radius?

I have data with the following normalized values: Unit vector for cylinder axis: -0.00270666, -0.01226211, 0.9999212 Normalized coordinates for cylinder center 0.01412114, 0.01074875, 0.00017004 ...
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Arc subtended by stretching of a conical spiral spring

I'm trying to work out the angle subtended by the stretching of a conical spring and I have a solution but I'm not 100% sure about it so would appreciate some feedback. An Archimedes spiral spring is ...
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1 answer
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Calculating area moment of inertia for a beam with underslung plate?

In a number of designs, a beam will have an underslung welded plate attached, as shown below: In this sketch, a symmetrical standard steel beam/column of dimensions H1 x B1, with web and flange ...
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3 answers
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Calculate area of mesh?

I have expanded steel mesh that I use to make garden cages: I would like to know how much sunlight the mesh blocks. I think I need to calculate the area that the mesh takes up (per square inch) and ...
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1 answer
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Equation used to obtain the adjustment angle of a pivoting lid support mechanism?

The following image shows a CAD model in its folded and unfolded form. I was able to successfully give it the ability for it to be adjusted between a 25 and 45 degree form, at 5 degree increments; ...
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1 vote
1 answer
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Building a half-arch of a specific height, while consistently using an angle divisible by 90

I am trying to construct a lift handle in the CAD Sketchup. The circled part of the image shows the arch I'm referring to. The program, Sketchup, has a 'tool' called push/pull, and another tool ...
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3 votes
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Wrap a geodesic dome with a poly sheet: Minimize overlap & loose areas

I want to make a geodesic dome greenhouse (16ft wide, type: 3V 5/8). Source: http://geodesicdomes.ca/wp-content/uploads/2009/12/domes-fullsize.jpg I would cover a geodesic dome frame with clear ...
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Difference in Diameter calculation using Solidworks and manually

When I try to create a flat form of a archimedes screw using Solidworks it gives me a diameter different from what is calculated manually basically using a Pythagoras Theorem. Can anyone explain the ...
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5 votes
7 answers
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What makes scooters unstable at high speeds?

Scooters and skateboards are obviously meant for slower speeds, below 5 MPH. Typically if you go faster than that, it becomes harder and harder to control the scooter, and you will fall off. An ...
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Boolean Geometry Help [closed]

I just don't get the concept of Boolean Geometry... Can you help me understand how to solve these homework problems? Thanks!
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How to find the nearest locations around a given latitude and longitude point? [closed]

I have a database of locations. Each location is a latitude and longitude pair. Now for each query, I want to get top "X" nearest locations around a given latitude longitude point. How do I actually ...
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1 answer
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Calculate attitude quaternion from 2 vector measurements

I am using a method proposed by R. G. Reynolds to estimate attitude based on two vector measurements, taken from: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19990052720.pdf Suppose we ...
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7 votes
3 answers
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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 ...
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6 votes
1 answer
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Do outer fillets|chamfers also reduce stress as inner ones do?

I kind of have an intuition or at least imagination about how fillet|chamfer of inner edges|vertexes reduce stress (concentration). But does that apply to outer edges|vertexes aswell? Maybe to a ...
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6 votes
4 answers
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Why are Whitworth threads angled at 55°?

You're probably thinking, "Well.. Why not? It's gotta be something.." Right? But 55° is kind of an odd angle if you think about it.. and it does seem like a pretty specific choice considering a ...
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How maps of globe, country or region were created few decades/centuries ago when modern technology like today did not exists?

What techniques were used to create the maps of a world, country or region when satellite or similar technology did not exists few decades or centuries ago?
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What does this equation mean?

$$\propto \dfrac {\text {Cross-Sectional Area}}{\text {Volume}} $$ I've seen this equation on my textbook (physics). Let us imagine that there are two pen with $7$ and $3$ lenght. Which is harder ...
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What is the most accurate geometry to represent earth

Currently software and maps represent earth in many different ways, the latest is Point Clouds as this is the most common surveying tools currently available. For the needs of visualisation, ...
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Advice for designing internal structure of glider wing

I am interested in designing a scale model semi-monocoque wing for a glider. I've done some research on the framework and internal structure. I have found out about the spars, ribs and stringers and I ...
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What is the deflection of planet-ring Gear Mesh along the pressure line and the position of the Plant gear?

For a Sun-Planet mesh in a planetary gear train, there will be a deflection $\delta_{sn}=\delta_{s}-\delta_{n}$ along the pressure line and the position of the planet will be determined by $\psi_{n}$, ...
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3 answers
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Graphene distribution over a sphere

How much graphene is required to coat a 5 inch (diameter) sphere if the graphene layer must be 35 nanometers thick?
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3 votes
2 answers
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How this radio knob converting a rotation into a straight-linear motion?

Few months ago I opened the boards of an old, scrap radio-cum-tape-recorder (Philips DR183); whose tuning knob (that adjusts the gang); was very peculiar. ( * I did not found its datasheet on web) ...
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1 vote
1 answer
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What is a void in CAD

I'm using existing architectural designs and some mechanical designs too, all CAD files in formats *.dwg, *.dgn and the drawings have smart solid geometries including voids. Using CAD software what is ...
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3 votes
2 answers
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How can I draw Voronoi regions in curved surfaces in AutoCAD?

How can I automatically compute and draw/display the Voronoi diagram of a given set of vertices on a surface in AutoCAD? A "Voronoi Sketch Generator" is the best I could come up with on a google ...
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1 vote
1 answer
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Diesel injector nozzle geometry

I thought of an injector nozzle for a diesel engine with an alternate combustion chamber format (somewhat like a Heron combustion chamber), and would now like to get an estimate of the size of the ...
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1 answer
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How should I calculate the centroid of a hollow structure when analyzing a wind load?

I am trying to solve the following problem: A masonry chimney having the shape of a conical frustrum is 25 m high. The external diameter at the top and internal diameter at the bottom is 2 m. ...
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Moment of Inertia of a Rectangular Cross Section

I have a question that is annoying me for a long time. I know that I can calculate the moment of inertia of a rectangular cross section around a given axis located on its centroid by the following ...
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Turbocompressor spool geometry

How come axial compressors always narrow and turbines always widen towards the rear? From what I know: The speed of sound of air increases with temperature, therefore increases (decreases) as it goes ...
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4 votes
2 answers
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AISC Section Modulus numbers

Why does the AISC handbook only list one figure for Section Modulus for shapes such as Angle(L) steel? Shouldn't there be two? The steel is asymmetric. Is the figure given just the Delta to the ...
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2 votes
2 answers
131 views

Lengths of Connectors in Steering Linkage

Below is a picture 4-wheel vehicle steering linkage. I figured that in order to steer correctly $(W+D)tan\theta_1=Dtan\theta_2$ where $\theta_1$ is the angle of the outside front wheel, $\theta_2$ is ...
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