Ask a physicist anything.

[Jazmyn]

Actual stupid questions asked

The below excerpts appeared in the Salt Lake Tribune. They were taken from real court records.

Now doctor, isn't it true that when a person dies in his sleep, in most cases he just passes quietly away and doesn't know anything about it until the next morning?

Q: What happened then?
A: He told me, he says, "I have to kill you because you can identify me."
Q: Did he kill you?

Was it you or your brother that was killed in the war?

The youngest son, the 20-year-old, how old is he?

Q: She had three children, right?
A: Yes.
Q: How many were boys?
A: None.
Q: Were there any girls?

Were you alone or by yourself?

Q: I show you Exhibit 3 and ask you if you recognize that picture?
A: That's me.
Q: Were you present when that picture was taken?

Were you present in court this morning when you were sworn in?

Q: You say that the stairs went down to the basement?
A: Yes.
Q: And these stairs, did they go up also?

Q: Now then, Mrs. Johnson, how was your first marriage terminated?
A: By death.
Q: And by whose death was it terminated?

Was that the same nose you broke as a child?

So, you were gone until you returned?

You don't know what it was, and you didn't know what it looked like, but can you describe it?

Q: Have you lived in this town all your life?
A: Not yet.

 

[Chesterton]

You don't know what it was, and you didn't know what it looked like, but can you describe it?

He must have been asking a physicist about the Big Bang.

 

[Jazmyn]

Q: You say that the stairs went down to the basement?
A: Yes.
Q: And these stairs, did they go up also?

M. C. Escher stairs again!

 

[Sanguis]

M. C. Escher stairs again!

His stairs go up, down, left right and inside out.

Those questions gave me some lulz.

 

[Chesterton]

This is from an actual deposition of the owner of a tree removal service in a Minneapolis case:

Q: Now, is the crew responsible to keep track of the number of trees that are removed or trimmed?

A: Yes.

Q: Okay. How do you train them to do that?

A: They are asked to count the trees that are going to be removed and they are asked to count the trees that are going to be trimmed. I believe they probably learned how to count through school.

Q: Is there any specific technique you give them to make sure they don't double-count or miss a tree as they do their counting?

A: A technique? In counting? I guess the only technique I'd have would be to start at the number one.

 

[sandwiches]

Actual stupid questions asked

The below excerpts appeared in the Salt Lake Tribune. They were taken from real court records.

Now doctor, isn't it true that when a person dies in his sleep, in most cases he just passes quietly away and doesn't know anything about it until the next morning?

Q: What happened then?
A: He told me, he says, "I have to kill you because you can identify me."
Q: Did he kill you?

Was it you or your brother that was killed in the war?

The youngest son, the 20-year-old, how old is he?

Q: She had three children, right?
A: Yes.
Q: How many were boys?
A: None.
Q: Were there any girls?

Were you alone or by yourself?

Q: I show you Exhibit 3 and ask you if you recognize that picture?
A: That's me.
Q: Were you present when that picture was taken?

Were you present in court this morning when you were sworn in?

Q: You say that the stairs went down to the basement?
A: Yes.
Q: And these stairs, did they go up also?

Q: Now then, Mrs. Johnson, how was your first marriage terminated?
A: By death.
Q: And by whose death was it terminated?

Was that the same nose you broke as a child?

So, you were gone until you returned?

You don't know what it was, and you didn't know what it looked like, but can you describe it?

Q: Have you lived in this town all your life?
A: Not yet.

It's a very common practice for lawyers to ask the same question several times in different ways to catch the people being questioned in a lie.

 

[Sanguis]

OK, here's a physics question.

If, in anti-matter, the equivalent to protons are anti-protons, and the equivalent to electrons are positrons, are the neutrons the same in both matter and anti-matter?

I mean, if anti-matter is just reversed polarity from normal matter, surely they must be the same, because neutrons have no charge?

 

[Cabal]

OK, here's a physics question.

If, in anti-matter, the equivalent to protons are anti-protons, and the equivalent to electrons are positrons, are the neutrons the same in both matter and anti-matter?

I mean, if anti-matter is just reversed polarity from normal matter, surely they must be the same, because neutrons have no charge?

Was wondering about this the other day, but there is a difference. Remember that neutrons are baryonic, so they're made up of quarks (udd). Flip the charge sign on those and what you're left with is a completely different set of quarks (ubar dbar dbar) - so they're noticeably different particles.

There are some particles which are their own antiparticles (known as Majorana antiparticles, iirc), trying to think what one of them would me....maybe quarkonia mesons (e.g. c-cbar, b-bbar) or something neutral but with no internal structure like a neutrino....

 

[Jazmyn]

Is there a diagram or something explaining all these particles?

 

[Jazmyn]

Is there a picture of all these particles?

 

[Cabal]

Is there a diagram or something explaining all these particles?

First diagram on this page contains the main fundamental particles discovered so far.

Standard Model - Wikipedia, the free encyclopedia

As for the particle zoo:

List of baryons - Wikipedia, the free encyclopedia
List of mesons - Wikipedia, the free encyclopedia

 

[JusSumguy]

It this new mole that appeared on my back cancerous?

It's a message from God to get your soul in order...

1. Why do stagecoach wheels turn backwards in movies?

Our eyes can't keep up with the speed of rotation - us seeing the wheel appear to slow down and change direction is our eyes lagging what's really happening.

Nope

It has to do with camera speed.

Thank you.

The camera shoots at 30 frames per second(29.97 actually). Up until that speed it's all good. As soon as the rotation exceeds the frame rate of the camera the wheel starts to turn backwards visually.
---------------------------------------------

I have a question.

Is light a particle or a ray (gas/amorphous)?

It seems to act both ways.

It goes through some things and bounces off others. In some cases the same light both bounces and absorbs in contact with the same object..

What's with that?


-

 

[Cabal]

E=mc2
Going backward, what is the number for c2?
Is it 299,792,458 meters per second, squared?

Yes, so approx 9E16 m^2 s^-2.

Is it one light year squared?

Nope. A light year is a unit of distance (equivalent to c * 3.15E7 or however many seconds there are in a year), c has units of velocity.

When it comes to E=mc2, what is the actual number used for c?

The one you gave. Physics works in SI units, so m s^-1.

I'm assuming that m= kilograms
Or is that incorrect?

SI units of mass are kilograms, so yes.

And how is E measured?

This is the energy equivalent of m kg of mass. Typically it's just calculated by using the E=mc^2 formula - however it can be checked experimentally for some cases, such as nuclear fission/fusion, matter-antimatter annihilation.

Typically, however, it's quite hard to fully convert matter into energy, as Wiccan_Child said, if you could do that with something fairly substantial you'd have a small holocaust on your hands. The Hiroshima blast was only about a gram's worth of matter changing into energy.

What is the number for E that describes the amount of work that can be performed by the force provided by mc2?

Not quite sure what you mean here....

What numbers (actual real world numbers) describe E and m and c2?

Well, c^2 is a constant, E and m are not. E and m will probably be variables in an experiment (one depending on the other depending on the setup).

For example, I have a mass of circa 77 kilograms (which sounds MUCH better to my ears than my weight of 170 lbs )

SI units are also largely metric, so nyer nyer imperialists

What is my energy potential, and how much energy could my mass expend (considering complete mass to energy conversion)

For some reason I'm not getting what W_C got.... 77*3E8*3E8 = 7.7E1*9E16 = 6.93E18 J = 6.93 EJ (exajoules). I was under the impression one essentially gets c^2 = 9E16 J of energy out per kilogram of mass fully converted.

 

[Jazmyn]

First diagram on this page contains the main fundamental particles discovered so far.

Standard Model - Wikipedia, the free encyclopedia

As for the particle zoo:

List of baryons - Wikipedia, the free encyclopedia
List of mesons - Wikipedia, the free encyclopedia

*brain implosion*

 

[Cabal]

Nope

Thank you.

The camera shoots at 30 frames per second(29.97 actually). Up until that speed it's all good. As soon as the rotation exceeds the frame rate of the camera the wheel starts to turn backwards visually.
---------------------------------------------

The same thing still happens with your eyes. Just at a different rate. We're as limited by our sample rates as a camera is. So it's not totally off, one would still see the same thing happen visually ourselves, just not necessarily at that speed of the vehicle going past.

I have a question.

Is light a particle or a ray (gas/amorphous)?

It seems to act both ways.

It goes through some things and bounces off others. In some cases the same light both bounces and absorbs in contact with the same object..

What's with that?


-

It's both a wave and a particle. In fact, this applies to matter as well. The wave nature or the particle nature shows up depend on how you're trying to observe it.

Wave–particle duality - Wikipedia, the free encyclopedia

So, e.g. when examined on small scales matter can be seen to diffract, but the rest of the time it's doing it's usual particle thang.

 

[Cabal]

*brain implosion*

Yeah, sorry about that. Particle physics is anything but well organised at times. That first diagram on the Standard Model wiki page is about the most concise description of the fundamentals but that still leaves scope for a whoooole lot of different particle freakery when you start building them up.

I'll see if I can dig out something less traumatising - that was just an introductory 2 min google to give you some links at least.

 

[Doveaman]

Why are rainbows always curved?

Why cant they be straight?

 

[Jazmyn]

A leprechaun is driving that car ^

 

[Cabal]

Why are rainbows always curved?

Why cant they be straight?

I can't explain it that well, but I know there's an optimal angle for viewing light backscattered from the inside of moisture in the air, so I think the curve of a rainbow is the effect you get of joining all those optimal viewing points up.

 

[Doveaman]

If redshift equals distant/velocity, why is the red spectrum in a rainbow connected to the other spectrums? Shouldn’t it be farther away?