Questions tagged [solid-mechanics]
288 questions
24
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3 answers
Could you compress chocolate such that it has the same density and shape as a real copper coin?
There are many cultures around the world that have traditions of chocolate coins around Christmas time, mine included. Recently I wondered if it was possible to compress chocolate to give it the same density as a real coin (which are mostly made of…
JohnMcSwag
- 353
19
votes
2 answers
Why and how is sound produced when two objects hit each other?
When two objects collide and undergo a partially inelastic collision (so every one we experience in every-day life), they rebound to a certain degree, but kinetic energy is not conserved. Thus, the energy of motion must be converted to another type…
usumdelphini
- 1,813
18
votes
1 answer
Why is paper inelastic but flexible?
Recently I have been studying solid structural mechanics, and one of the points I find really confusing is how elasticity and flexibility are closely intertwined.
Consider an Euler-Bernoulli beam, for instance. The flexural rigidity of the beam is…
FLP
- 327
16
votes
4 answers
Hollow shaft vs. Solid shaft: Which one's more resistant to torsion?
I recall being told once that hollow rods/shafts tend to resist torsion more than solid rods/shafts...but I wasn't told why this is the case.
Now that I'm a little older, running this "fact" through my mind, my intuition tells me that a solid rod…
Alan
- 289
15
votes
3 answers
Continuum limit for solid mechanics
Is there a rigorous derivation of the limits for continuum properties in solid mechanics? For instance, the stress-strain relationship may be linear for large samples (the slope being the Young's Modulus) but at what limit does that break down?…
tpg2114
- 16,815
15
votes
1 answer
Why does the cross section of a metal after a hypervelocity impact look like that?
Look at this image of a cross section of a piece of (I assume) metal after a hypervelocity impact:
I understand where the crater shape comes from, but what puzzles me is the cavity near the bottom: How did this form? Is this a usual feature that…
paulina
- 3,488
12
votes
1 answer
Why doesn't a bus blow due to internal pressure?
When one travels in a bus, if he's sitting at any window, he will feel that the air is coming inside. If someone is standing at the open door of the bus, he'll also feel that the air is coming inside.
If so much air is coming inside, why doesn't…
user24503
- 121
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12
votes
2 answers
Is Young's Modulus a Lorentz Scalar?
If a spring is at rest and lies along $X$ axis in a frame $O$ with a spring constant $k_{0}$ then its spring constant in a frame $O'$ which is moving with a speed $v$ at an angle $\theta$ with the $X$ axis (the motion is as observed from $O$) comes…
user87745
10
votes
1 answer
Is there a solid material with low acoustic impedance and low attenuation coefficient?
Is there a solid material with both a low acoustic impedance (specifically, an acoustic impedance as close as possible to that of the air) as well as low attenuation? In other words, is there a material that allows a substantial portion of an…
The Riddler
- 327
10
votes
6 answers
Why rubber is incompressible material?
Why rubber is incompressible material? I know its Poisson's ratio is nearing to 0.5. So I don't understand physically, what it means by 0.5 Poisson's ratio and incompressibility. When I tried searching it, I found that rubber (or similar polymers)…
user3705273
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9
votes
3 answers
Is there any dynamical reason for the winter solstice to happen close to the perihelion?
When the winter solstice arrives, the angular momentum of the Earth, its orbital angular momentum and its radius vector with the orbital focus in the Sun are in the same plane. This happens quite close to the perihelion (~2 weeks later), where both…
Eduardo Guerras Valera
- 3,805
8
votes
4 answers
Addition of forces on a rigid body instead of a point
When two forces act on a point mass,we add the forces like we usually do and i have no problem understanding that. When the same forces are applied on a rigid body,how are we able to add them the same way?
In the first diagram,what we have is a…
madness
- 1,205
8
votes
2 answers
Why are springs spiral-shaped?
I've had this question on my mind for quite a while and looking at the web, I couldn't find an answer to this question.
I've had a lot of physics experiments involving springs, unintentionally dismantled a hair clipper once, helped my dad repair his…
user226894
8
votes
3 answers
Is it possible to reassemble a perfectly cleaved crystalline solid?
This is a purely theoretical question about "perfect" solids under "perfect" conditions.
Assume you have a crystalline solid with a perfect crystal lattice (i.e. no defects). Let's imagine a cube of pure diamond, perhaps 2 cm^3 in volume.
Now…
7
votes
1 answer
Why the upper section falls faster than the bottom section when the line is cut?
This question is from the book Problems in Elementary physics - Bukhovtsev et al. question number 78. It goes like this:
A homogeneous cube is hanging from a line. The line is then cut. Which parts of the cube will have a greater acceleration at…
hellofriends
- 257