Science Questions

[Dutch guy]

Since I have never ridden a roller coaster myself nor have I ever been taught the relevant physics, I was wonder if someone could explain to me the relevant physics to this problem?
This so I can create more realistic creations that don't piss off physicist viewers.

Wait, wut? Never? You should get that fixed Coasters are FUN!


To gauge where to start with this explanation, what is your understanding of physics in general? (Do you understand for instance the concept op an acceleration "causing" a force on a mass? And the ideas behind circular acceleration, commonly called centrifugal force?)

[Merrymaker_Mortalis]

I understand Positive Force. I understand Negative Force. I understand Lateral force. I understand laws of Energy. I understand friction.

What I don't understand is appropriate speeds for certain actions.

I understand going too fast round a corner is bad. I just have no idea when you're too fast for doing a Vertical Loop or an Inline Twist.

I am told that the height of each successive hill and inversion should be progressively lower. I do not know why it's bad to have a much smaller hill and then slightly higher hill.

The knowledge I am ignorant about is knowledge gained by experience riding a coaster. And anything I am ignorant about. Ignorance about my ignorance
--
They were also viewing work about 2 years old. So I don't know how out-of-date their viewing of my knowledge is. I can't risk assuming I've already resolved my problems with coaster design.

[mariomario42]

I am told that the height of each successive hill and inversion should be progressively lower. I do not know why it's bad to have a much smaller hill and then slightly higher hill.
.

To maintain the most energy and to get the most vertical displacement for your buck, it should be in descending order. A small hill is lowering the potential to gain your height back if it's the first inversion. From a real world standpoint it would make a large difference with requiring more of the chain lifts to complete the ride, but in RCT3, it doesn't matter in the slightest.

For something to be harsh on a rollercoaster, it's probably an uncomfortable amount of G's on your body. Something like a inline twist/barrel roll is changing the direction on the body when inertia wants you to go forward and can be a cause of discomfort/disorientation. These are fine when you are going the appropriate speed, but in a game, it would be easy to going to fast for these features.

What these speeds are exactly would require some research.

[Merrymaker_Mortalis]

So I suppose, in the mean time, ignore criticism of this nature until one of these criticisers actually explains what they mean? I have asked them and they still haven't replied (if you're going to make a criticism, at least suggest a resolution rather than pick holes. Sorry, not everyone who is into roller coasters understand the specific fine physics behind them). Would be nice if they specified which elements were problematic. Because I can personally guess, but I would never know.

The thing is, I don't like trains going too slowly through elements because you get "hang-time" where gravity starts taking a stronger hold and the hypothetical riders push up against their restraints/lap bars. Or travelling slowly is dull.

[Lord Chrusher]

When going around any corner, higher speed means higher acceleration.

Also if gravity is feeling stronger, why are the riders pushing up against their restraints?

The human body can also handle only a limited amount of jerk. Jerk is change in acceleration the same way acceleration is the change in velocity. The human body can handle constant acceleration quite fine but needs time to adjust to changing acceleration.

[Merrymaker_Mortalis]

Also if gravity is feeling stronger, why are the riders pushing up against their restraints?

"Centrifugal Force" (I know that term isn't correct, but I can't remember the accurate term), tends to keep the riders in their seats as a train navigates a inversion that is loop-like in appearance. The higher the speed around the element, the stronger the force. However, this may not be comfortable, and travelling at that speed round a tight element will be highly disorientating. The job of the rollercoaster is to thrill, not torment. By approaching the element slowly, the element is enjoyed more. But if the coaster sorts of dwindles at the top, gravity is going to pull you down-through your restraints.

A bit of hang time is thrilling. Too much is uncomfortable.

https://www.youtube.com/watch?v=Y4cotS07mXQ This is pretty much the ideal behaviour of a train performing a "Vertical Loop".

The human body can also handle only a limited amount of jerk. Jerk is change in acceleration the same way acceleration is the change in velocity. The human body can handle constant acceleration quite fine but needs time to adjust to changing acceleration.

The only time you have sudden change in speed when constructing roller coasters in any environment (virtual or real) is when you have an intervention in the form of a break. In RollerCoaster Tycoon 3 it can be challenging working out how to reduce a train's speed from about 60 MPH down to an acceptable 10/5 MPH. The speed you reduce to depends on the purpose of the breaking. Generally you'll always want it to be slow. Breaks are a way to split the layout into sections. This allows multiple trains to travel on the layout safely. If the track ahead is not clear, then the train being braked will be stopped still. The train will be allowed to proceed when the way ahead is clear. You probably have a section free of no trains because loading times of trains are unpredictable (usually all big rides are packed). Also the Park can run one fewer a train if traffic is slower than normal.

[Hepheastus]

Also if gravity is feeling stronger, why are the riders pushing up against their restraints?

"Centrifugal Force" (I know that term isn't correct, but I can't remember the accurate term)

Centripetal Force is the term

[Merrymaker_Mortalis]

Ah thanks. Stupid Google thinks the former term is correct, and I wasn't able to avoid it.

[My pseudonym is Ix]

Centrifugal force is actually a thing, but only with respect to a rotating rather than static reference frame. If you want, I can give you an as near as possible complete explanation of the basics of rollercoaster physics, but bear in mind- it will be very long and will have to wait a bit as I'm going out this evening

[Merrymaker_Mortalis]

If it would cut down on the amount of information you required to dispense: I only need to enquire about the physics behind "complex" elements such as inversions.

This information might even help me understand the active role of track supports better: I could recreate more realistic steel track supports.

[My pseudonym is Ix]

OK- I'm about to go out, but should be back around 10 ish. Expect a response by 11 (probably)

[Merrymaker_Mortalis]

One thing I am not sure about is: At what point is it more appropriate for a bend on the track to have a bank of 45* ( \ ) as opposed to 90* ( | ) to minimise rider discomfort?

Is that question even easily answered cold?

[Smeghead]

So I'm working on a story idea that kind of hinges on a scientific fact that I've yet to find a answer to.
Are natural antimatter particles mostly found in the "belts" around planets? Or can they occur around stars or in empty space? In which case; which would have the highest concentration of it?

[Master Gunner]

Antimatter particles are contained in our magnetic field (they're actually produced there, as neutrons interact with cosmic rays), and would likely be found in any strong magnetic fields (so stars as well). Here's an article about it.

I believe antimatter floats around in interstellar space too, though in lower concentrations than you'd find in a planet or star's magnetic field. In theory, large amounts of antimatter would coalesce into nebula, stars, and planets of their own, but as far as I know we have never observed such phenomena (which is actually one of the bigger mysteries in astronomy - why there's so much more matter in the universe than antimatter).

[My pseudonym is Ix]

One thing I am not sure about is: At what point is it more appropriate for a bend on the track to have a bank of 45* ( \ ) as opposed to 90* ( | ) to minimise rider discomfort?

Is that question even easily answered cold?

That's a difficult question to answer from a purely physics standpoint; in general, and from personal experience of coasters, I'd say that high speed corners require steeper banks; that way the added centripetal force holds the body more upright, counteracting gravity pulling the person down.

...I had written out a very long, detailed summary of work-energy and the forces acting on a coaster, but then I realised that it probably would be of only limited use to you. So instead, I will embark on a quick summary of probably the most important force in rollercoaster design- centripetal force.

Newton's second law tells us that to change the direction of a coaster's velocity requires an acceleration, and that acceleration requires a force to cause it. When an object is travelling round in a circle (or part of a circle), the direction of its velocity is constantly changing. By way of an example, if you imagine one of the tips of the tails on Kapol's signature perpetually spinning round, at one moment it'll be moving downwards, then it'll spin round and start moving towards the left, then it'll spin some more and suddenly it's velocity is directed upwards. The direction of its velocity is changing, and this requires it to be accelerated inwards towards the centre of the circle. This is centripetal acceleration, and requires centripetal force to cause it.

(Centrifugal force is what our bodies 'feel' as a sort of opposite of centripetal force, as we feel ourselves being thrown outward with the same force causing us to be accelerated inwards. It's more complicated than that, but isn't relevant right now)

Centripetal force is important partly because it is one of the best ways of subjecting a coaster and its occupants to lots of acceleration, or controlling the acceleration & resultant force acting on the coaster. The formula for centripetal force is F=(mv^2)/r, where m is the mass of the coaster, v is its velocity and r is the radius of the curve it's travelling round; that's why the 'ideal' vertical loop for a train is more elongated than a circular loop, so that as the train slows down (v decreases) the track curves more steeply (r decreases) so the amount of centripetal force acting on the body stays constant. That way, you only get 'hang time' similar to what you would get from being projected straight up and falling straight back down, which feels 'right' for the coaster's occupants (that's an awful explanation, but I'm trying to keep things vaguely simplistic).

From that, it's best to deal with things on a case-by-case basis; the only general rule worth remembering is that tight, fast turns (where centripetal force is high) will need lots of track supports to cope with all the centripetal force required. So... sorry if that wasn't as enlightening as you might have hoped, I suggest if you've got anything more specific you want to know you ask it as a specifically phrased question

[Lord Chrusher]

You are not going to find significant amounts of antimatter anywhere I am afraid. Antimatter does make up an absolutely tiny amount of cosmic rays which can be found flying through space everywhere. You are going to find more antimatter near where cosmic rays are produced - supernovae and active galactic nuclei but not significant amounts. More antimatter is produced when cosmic rays collide with something, such as a planet's atmosphere. Some of these secondary antimatter particles do get temporarily trapped by magnetic fields so you do get a higher amount of antimatter there. However in absolute terms there is an insignificant amount of antimatter there.

[Merrymaker_Mortalis]

@IX Don't worry. The critique I received was very vague. I have no idea how I can be more specific without me forcing you to watch footage of every different element of my previous projects and ask: "Would that kill/hurt you?"

That wouldn't be fun for either of us.

Thanks for the information. I found the information about the supports very helpful. It also reaffirms some of my suspicions about some coaster physics.

I think what I can conclude, is in the future if someone critiques my ignorance about physics in the context of roller coasters, I have to challenge them and ask why and where.

[Smeghead]

Thank you, that's all I needed to know (and it was the answer I hoped for, so now my idea makes sense)

[Hepheastus]

So I'm working on a story idea that kind of hinges on a scientific fact that I've yet to find a answer to.
Are natural antimatter particles mostly found in the "belts" around planets? Or can they occur around stars or in empty space? In which case; which would have the highest concentration of it?

My understanding of Antimatter is that you won't find large amounts of it anywhere because of the explosive effect antimatter has on matter. If an antiparticle meets it's corresponding matter particle (say a positron interacted with an electron) they would annihilate each other producing a huge amount of energy and two gamma ray photons

[Smeghead]

That much I know

[AdmiralMemo]

I believe antimatter floats around in interstellar space too, though in lower concentrations than you'd find in a planet or star's magnetic field. In theory, large amounts of antimatter would coalesce into nebula, stars, and planets of their own, but as far as I know we have never observed such phenomena (which is actually one of the bigger mysteries in astronomy - why there's so much more matter in the universe than antimatter).

Question: Out of the billions of galaxies out there and countless billions of billions of stars out there, how do we know one isn't made of antimatter? Would there be a different "signature" for an "antimatter star" than a normal star of the same type that we could look for?
Could there be an "antimatter galaxy" out there that we have seen but just haven't realized is made of antimatter yet, and is isolated from other galaxies via the intergalactic void, so it hasn't exploded yet?

[Master Gunner]

It's true that a purely antimatter galaxy would, to the best of our knowledge, be indistinguishable from a purely normal matter galaxy as far as our telescopes are concerned. We primarily detect antimatter by the gamma rays given off when it interacts with normal matter.

However, an antimatter galaxy would still likely contain trace amounts of regular matter. Our own galaxy has a sizable cloud of antimatter around the center of the galaxy, though I don't know how detectable that would be from another galaxy. I believe NASA is looking at colliding galactic clusters for signs of annihilation events in order to locate antimatter galaxies.

[Hepheastus]

Answer: Theoretically yes. Probably no, but we don't know

To quote Douglas Adams "Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space."

Seeing as how space is so big and all we simply don't know one way or another whats out there. It is theoretically possible for antiparticles to make antimatter, antihydrogen is fairly well documented but nothing bigger than antihelium has ever been created or observed. Certainly the visible universe doesn't contain large antimatter constructs. As for why this is, it's a mystery
There is a module currently on the ISS that is scanning for antimatter particles in the universe, It's the Alpha Magnetic Spectrometer.

[AdmiralMemo]

Certainly the visible universe doesn't contain large antimatter constructs.

Going back to my question: How do we know this for certain? What would be the "signature" of a large antimatter structure that distinguishes it from an ordinary matter structure? And if we don't know what the "signature" would be or there isn't one, then we cannot know for certain that currently-observed structures are not made of antimatter, until and unless they directly interact in some way with something that is known to be normal matter.

So, the key question I'm asking is "Is there some way for us to detect whether something is made of matter or antimatter other than direct interaction with matter?"

I mean, antimatter does have the opposite electrical charge of matter. But how would we detect that in stable atoms or molecules, especially from afar? Would an anti-star give off a different spectral reading or something?

Edit: Just to clarify, I'm really looking for a "How can we tell?" answer, rather than trying to debate whether it exists or not. If there is a method, then I assume that scientists are using it already.

Alpha Magnetic Spectrometer

What does this thing actually do? How does it detect antimatter?

[Merrymaker_Mortalis]

Does antimatter have anything to do with Black Holes? Or is their only connection is "obnoxious to observe"?