/sci/ - Science and Mathematics

>>1939

A class :^)

>>1940

The engineering stuff looks like it's fun to know but I've no idea how this plays into an Astronomy degree.

Do you want to do astronomical research or do you want to have an input into the design of telescopes/observatories?

>>1944
No seriously I have no idea what you're trying to say. Is "course" the word you're looking for?

>>1946
course, class, module
The smaller courses that make up a degree.

bump

My advice to you OP is just forget about such labels.
In my experience (easily) more than half of all debates on this topic are completely based on people having different definitions of what those words mean, and they often don't even realize that that's all it boils down to. It's such a waste of time.

All that really matters as far as I'm concerned is that people acknowledge that they can't be certain. Whatever they want to consider to be the "most likely case" on top of that is up to them.

>>1949
I'm a scientist. Am I the only one?

>>1927

Wouldn't the centre of lift come from integrating the pressure along the surface?

And the centre of lift will be perpendicular to its position on the surface?

If the lift is at an angle, should you find the appropriate x or y component and use this force for the moment?

>doing fluids on planes
>doing fluids at all

>>1827
>>1828
>>1829
im pretty sure life couldnt work without a polar solvent.

>>363
well they might work slow as hell.
Suppose my 93K analog wanted to type this post. It might take him hours.
Of course, assuming life there started evolving the same time it did here they would be far behind.

Titan has water in the form of ice. It could be that lifeforms just use water in the smallest possible quantities (like individual molecules here and there that are too spread out for ice crystals to form), and are composed mostly of other chemicals.

Titan might also have a mixture of liquid water and ammonia below its surface, so it could be that all life just dwells there and uses thermal vents for energy.

>>1864
So aside from Water and Ammonia, what other compounds could be used as a medium?
Like the other anons said, methane isn't terribly realistic because it can only dissolve non-polar compounds.

>>1914
Maybe a mix of water and ethylene glycol?
That only protects against freezing up to about -30°C.
Methanol is polar, but has a melting point of 175.6 K.
What we're looking for is a solvent with a melting point below 93 Kelvin.
Which is not that easy because polar liquids are by nature less volatile than non-polar ones, and any I know of are frozen solid at 93 Kelvin.

>>166
Logic as we know it would not exist either, and therefore there would not be a prevention of things forming.

>>166
>that not even nothing exists.
FTFY

If the mathematical universe hypothesis or a related theory is correct, then "existence" drops out of the equation, and what seems like existence would refer to how mathematical structures relate to the mathematical structures that are us. "Non-existence" would be simply fundamentally false.

If it does have physical meaning to assign an objective binary number (or maybe a real or complex one with absolute value less than or equal to 1, given quantum mechanics) to a mathematical concept to say that it exists or not, then if nothing exists, only nothing would exist. Nothing would happen, and only nothing would happen.

Nothing not existing violates axioms of logic, as made clear by it contradicting the statement that nothing exists. If that were true, that would amount to a provable inconsistency in logic as we know it. As we've known to be an option since Gödel. If what you're saying is true, there may still be other logics which "exist" in some sense familiar to us, or there might not be. Or a third option; no reason to discount that possibility if logic is fucked. The alternatives would be almost literally inconceivable though.

>>166
>What if nothing existed?
Well then there would be nothing…
> And by that I mean, existence was in such a state of non-existence, that not even nothing didn't exist.
Then it would be a paradox? It wouldn't really matter since there's nothing.

>>166
>that not even nothing didn't exist
you just blew my fucking mind

>>1898

Depends on what type of diagram you're doing.

Wtf is your diagram?

>>1898
Powerpoint for shitty 5 min figures.

Paint.NET for quick touch up/basic cropping.

yEd for graphs.

Illustrator for high quality figures.

I've been meaning to learn tikz for a while but seems like too much work.

>>1887

Neato.

Care to share how you're doing it?

>>1889

It'd be my one true pleasure.

http://jsfiddle.net/b1xhyny2/1/

feel free to fiddle with the spirals or fork me if you have some cool ideas.

That's because of the direction of the force applied in relation to the screw's face.

For the shear modulus to be used instead of Young's modulus (the tensile modulus), the force must be applied parallel to one of the solid's faces while the opposite face experiences an opposing force.

The actual manner in which the solid deforms does not affect which modulus is used. Only the characteristics of the applied force determine that.

Example:
If you considered a perpendicular force pressing down on a cylinder, when the cylinder begins to break it will do so in an unpredictable direction.
The screw is unusual because it seems very obvious which way it will break but, as stated, that actually doesn't affect which modulus you use.

>>1853
I just want to also ask, how can a perpendicular force press "down"? Perpendicular to what then? What picture are you trying to paint?

>Only the characteristics of the applied force determine that
>Only the characteristics
So, you don't look at what it is but instead, look at what "class" it belongs to.

>>1856
>Does the cantilever beam have shear stresses inside of it because there is an applied force that is parallel with the front-end face and the reaction force applied by the wall at the left-end of the beam?

Yes. In your free body diagram the wall is fixed in the x and y directions and because it's not a pivot, moments.

A shear force is where two planes are acting in opposing directions.

Shear stress Q is equal to the vertical components in the wall - the vertical components of the force.

Force F has x and y components though in this case the x component is zero.

>Does this affect the shear?

No. Unless the force is moving with the beam it will remain completely as a Y component.

Post too long. Click here to view the full text.

>>1857
A force is a vector, and as such the only 2 qualities needed to determine a force are direction and magnitude.

You don't need to consider magnitude for this problem, obviously. All that matters is the direction of the force in relation to the object's sides.

>>1785

The material will break before it will plastically deform.

Like a rubber block. You can rip and tear it but its pieces are largely always going to return to the original shape.

>>1793

When you say the material "stretches" you're talking about "strain".

Strain is defined as
(Change in Length / Original Length)

Take rubber as an example. It stretches until it breaks. After it breaks look at the two pieces, put them together and they're still the same shape. They underwent elastic deformation not plastic. The material has not exceeded its yield strength.

Yield strength is the point at which plastic deformation occurs.

Young's modulus or Elastic modulus is the point of material failure. (Stress in the material / Strain).

You can stretch and bend and apply forces to all materials and they will experience strain. So long as these forces are kept under a limit then when the forces are relieved, the material will return to its original size and shape.

Post too long. Click here to view the full text.

>>1807
I see. While this clarifies your original response, this still doesn't answer my follow-up question: How do you plastically deform a material if it breaks before it can plastically deform?

Now I have a new follow-up question: Young's Modulus is the point of material failure? That's not consistent with its definition on wikipedia or anything I've read anywhere else about it.

Well damn.

I thought it was going off on the fourth; was it moved up?

Also, pic very unrelated.
Should've done a Space Engine render, would've been appropriate.

>>1515
Fucking saved.

>>1515
simply beautiful

>>1411
so there are more stars in my universe than in yours? :^)

>>1411
>galaxies in the universe,
I'm pretty sure we don't know how big the universe actually is, as we can only possibly see 47 billion light-years away.

Do you want to be surrounded by scientists or SJWs?

>>1851
Oh look, one of those extremist math/physics jihadists.
You know you people are still welcome on halfchan?

>>1862
This. Its not like any of those two things have anything to do with this board. OH WAIT

>>1862

>Physical
Scientists studying the evolution of humanity.

>Cultural
SJWs bitching about patriarchy.

It's a joke anyway.

Conversion kits.
At first very expensive for classic cars only ("Ya want the one that leaves the steering wheel or the one with the tray table?") Eventually they will come down in price.
It likely IMO that public sentiment will allow people to operate their own cars under certain circumstances. Even at their best computers do some very stupid things and a human as a backup is a good idea.
"I'll keep the steering wheel."

>>1859

> Even at their best computers do some very stupid things and a human as a backup is a good idea.

There can be an "emergency brake" for special situations but from what I've read self driving cars are far safer than human drivers. On a personal basis, even if you're a competent driver you can still get fucked over by someone who's an idiot, drunk, or impaired in some other fashion.

Computers don't have to be perfect, they just have to do be better than humans. When it comes down to insurance companies, humans will look several times more risky than computers ever could. Think of your premiums going from brown station wagon of a 40 year old lady to red corvette of a 16 year old druggie who's been in multiple fender benders. Even if you pass the multiple tests required for the special license you will find insurance payments alone to be cost prohibitive for public roads.

>It likely IMO that public sentiment will allow people to operate their own cars under certain circumstances.

Like I said, hobbyist will exist. I have a circle of friends who are really into juicing up cars. They take them to racing tracks and enjoy the exhilaration of racing against gear heads.

There are many people like them and they're a market that will need to be catered to. So there will be public race tracks that already exist and others built to accommodate those who like racing. Also if you like off roading that will be fine as well since many "off road" tracks are either private or far enough off the beaten path to not warrant a special license.

This will also ensure you don't have illegal street racing. I'm assuming in my scenario legislation is in place to make driving on public roads a felony offense along with being grounds for revoking recreational driving licenses (for endangering the public of course).