General questions (1 Viewer)
- Thread starter Glyde
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There's a thing called Google.
Anyway, a truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements forming triangular units.
A box girder bridge is a bridge in which the main beams comprise girders in the shape of a hollow box. The box girder normally comprises either prestressed concrete, structural steel, or a composite of steel and reinforced concrete.
Got it from Wikipedia.
On the Excel Senior High School Engineering Studies (author by Peter M & Roger M) text book page 28, where I'm introduced to the Engineering Mechanics and Hydraulics, there's an example where the area is divided by 4.
I'll rewrite the work:
Tensile stress
Determine the Ultimate Tensile Stress (UTS) of a 15mm diameter rod if the maximum load it can withstand is 70 kN.
Load = 70k x 10^3 N
Diameter = 15 mm
Area = pi15^2 divide by 4
= 176.7 mm^2
...and then it continues with
UTS = L/A
But I want to know where the "divide by 4" comes from?? Is this textbook even reliable?
I'll rewrite the work:
Tensile stress
Determine the Ultimate Tensile Stress (UTS) of a 15mm diameter rod if the maximum load it can withstand is 70 kN.
Load = 70k x 10^3 N
Diameter = 15 mm
Area = pi15^2 divide by 4
= 176.7 mm^2
...and then it continues with
UTS = L/A
But I want to know where the "divide by 4" comes from?? Is this textbook even reliable?
Nailgun
Cole World
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I don't think I'll ever work out what exactly it is you do lol
^2 \\ &= \pi \cdot \frac{d^2}{4}.\end{align*}$$)
Are you an engineer, mathematician, chemist, physicist, medical doctor - who knows lol
Thanks. Wasn't sure if they could've just half the diameter instead of making it more complicated. But now I know a new (probably redudant) equation and that some maths here will try and be tricky. I'll be sure to ask again when I'm bewildered.
Hai again. I'm irritated at a question and I'm not entirely sure how the conversion thing goes. I've got the numbers right but I don't got the numbers in the right places... See below:
It's from a book called Engineering Studies The Definitive Guide.
Q. Find the resistance of a copper wire used in an appliance that is 300mm long, and has a diameter of 2mm, if the resistivity of copper (at 20oC) is 1.7x10-10 Ohm metre.
The formula given is R = p x l/a
where
R is the Resistance (Ohm)
p is the resistivity (Ohm m)
l is the length (m)
a is the cross sectional area (m2)
Here's my work out:
R = (1.7x10-8) x (0.3)/ pi(3.141...) x 0.001
= 0.00000162338 Ohm
And, the answer given was 1.62 Ohm m
I thought I got the conversion wrong but I'm really not sure now.
It's from a book called Engineering Studies The Definitive Guide.
Q. Find the resistance of a copper wire used in an appliance that is 300mm long, and has a diameter of 2mm, if the resistivity of copper (at 20oC) is 1.7x10-10 Ohm metre.
The formula given is R = p x l/a
where
R is the Resistance (Ohm)
p is the resistivity (Ohm m)
l is the length (m)
a is the cross sectional area (m2)
Here's my work out:
R = (1.7x10-8) x (0.3)/ pi(3.141...) x 0.001
= 0.00000162338 Ohm
And, the answer given was 1.62 Ohm m
I thought I got the conversion wrong but I'm really not sure now.
Last edited:
Someone help explain where does the longitudinal force exist on a body/subject.
Examples I'd like to know... A Cube, an airplane and a bridge. I'm just not really certain of the definition and prefer a picture, but I haven't been able to find much.
Examples I'd like to know... A Cube, an airplane and a bridge. I'm just not really certain of the definition and prefer a picture, but I haven't been able to find much.