Spiders Perform This Cool Trick With Their Web

Calculus Level 2

The above image shows a spiderweb that is heavily laden with morning dew.

Which of the following best describes the shape of each segment of the web?

Image credit : Wikipedia
Half an ellipse Straight line Parabola Catenary

Chung Gene Keun by Chung Gene Keun , 42, USA

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8 solutions

Francis Naldo
Mar 2, 2014

Catenary is the curve where there is no upward force acting on any point between the endpoints(place where it is supported) of any string-like objects. (Assuming that their are no external forces acting on except the gravity.)

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I answered Parabola.... I don't know what is catenary is... The image is likely close to what is parabola is, that's why. that's my logical reason which isn't logical hahaha

Adrian Hansen - 7 years, 3 months ago

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Even though they look similar, a catenary which is in the family of hyperbolic curves best describes the shape of any hanging mass. This is because caternaries are what best minimize the potential energy configuration of hanging masses.

Thaddeus Abiy - 6 years, 4 months ago

no sir, where is the Directrix, what will be the latus rectum? Can't fit in all of that. ....Half ellipse will sound funny as where will be the two focuses be? Straight line fails to fit in...Now nothing more is left.

Simran Arora - 7 years, 3 months ago

Ya i also thought the same way

Shubham Raval - 6 years, 10 months ago

Thank you. :)

Krishna k - 7 years, 3 months ago

thanks

Fahad Khan Khan - 7 years, 3 months ago

I am happy to know that, my answer is correct.

পন্ডিত চোদনা শঙ্কর - 7 years, 3 months ago

the correct answer is Catenary because the web sagged due to the weight of the morning due. It can't be parabola because parabola may open downward. Cable/web sag only opens upward. :p :)

Joann Sinamban - 7 years, 2 months ago
Robert Fritz
Mar 1, 2014

I searched catenary because I didn't know what it was, and your image that you used for the question was in my search.

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But parabola & catenary look similar. look at this A picture from Wikipedia image image

Maharnab Mitra - 7 years, 3 months ago

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It's not the similarity but what it's used to define that is the pertinent point: in physics and geometry, the catenary is the theoretical shape a hanging chain or cable will assume when supported at its ends and acted on ONLY by its own weight. A parabola, in comparison, is a Cartesian mathematical construct of the form y^2=4ax The question was about a spider-web, not a graph.

Akshay Jamwal - 7 years, 2 months ago

If you extend both, then you can find which one is correct.

Harshal Sheth - 7 years, 3 months ago

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Can you give me the equation of catenary curve? I know parabola: y 2 = 4 a x y^2 = 4ax

Maharnab Mitra - 7 years, 3 months ago

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@Maharnab Mitra – its an cosine hyperbolic function y=acosh(x/a) where a is the scaling parameter

manish girdher - 7 years, 3 months ago

In principle, they aren't similar. Catenary (imagine cable sag) only opens upward due to external weight creating the sag. Parabola may open upward or downward. :p

Joann Sinamban - 7 years, 2 months ago

catenary and hyperbola are similar, not the parabola. hence the option doesn't contains Hyperbola.... i hope, the difference between hyperbola and parabola are known.

Anand Narayan - 7 years, 3 months ago

i did the same!!!

Utkarsh Yadav - 7 years, 3 months ago

i did the same btw

Al Baihaqi - 7 years, 3 months ago

The curve has a U-like shape, superficially similar in appearance to a parabola, but it is not a parabola: it is a (scaled, rotated) graph of the hyperbolic cosine. by wikipidia

Vandana Verma - 7 years, 3 months ago

I put parabola, because I didn't know what was catenary.

Katryn Pontes de Oliveira - 7 years, 2 months ago
Arijit Banerjee
Mar 1, 2014

Its given in wikipedia!!

3 Helpful 0 Interesting 0 Brilliant 0 Confused

The answer is catenary. It is an idealized hanging chain or cable assumes under its own weight when supported only at its ends. The curve has a U-like shape, superficially similar in appearance to a parabola, but it is not a parabola.

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Kho Yen Hong
Mar 1, 2014

You can get some of info from Wolfram MathWorld

http://mathworld.wolfram.com/Catenary.html

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In physics and geometry, a catenary[p] is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends.

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Bright 15 year old kids of my country. You all will make India proud some day.

Simran Arora - 7 years, 3 months ago
Rohan Kumar
Mar 4, 2014

I knew it was not the half of ellipse not the parabola not the straight line and i have no idea about the catenary so i mark the catenary

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Shreyashi Pal
Mar 2, 2014

i just crossed all the wrong answers and catenary was the one i was left with.

0 Helpful 0 Interesting 0 Brilliant 0 Confused

How did you Know that it is not a parabola?? Both look the same 2 me..

chinmoy dutta - 7 years, 3 months ago

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