Physics for dummies .

[Hugger-4641]

Did they do it with a smooth or rifled bore?

I would think it doesn't matter, but they used a 1911.

 

[Bob Willman]

you should explain gravity on Earth of is Fg=9.8m/s

But your bud is correct, a bullet in deep space will never drop. Because of the lack of gravity and lack of up & down

So my solution is… drink a beer and be like “Bro, you like 10mm, then we cool” what I’m trying to say is: you can’t teach what someone don’t want to learn

Any object in deep space will fall to somewhere if it is has no velocity. There is gravity everywhere in space. I am not aware of any object in space that has no velocity. There are a bazillion objects that are orbiting about other objects, but they all are falling. It is just that the centrifugal force makes them appear to not be falling. If their velocity were to stop, the fall would happen immediately.

 

[mcb]

Did they do it with a smooth or rifled bore?

Rifled, 1911 IIRC.

 

[d2wing]

Physics as in applied Ballistics is very hard to explain to many gun guys. Quackery sells much better than physics and real ballistics. The popularity of thumper cartridges and the TV image of a shotgun knocking people through doors etc.

 

[230RN]

Congradulations! That's how (more or less) Newton described an orbit.

https://en.wikipedia.org/wiki/Newton's_cannonball

I already pointed that out with a neat diagram in:

https://www.thehighroad.org/index.php?posts/12561595/

Incidentally, re a "horizontal" barrel --with many guns, the barrel is actually pointed down with respect to the sighting line. Hatcher explains this as due to the recoil which occurs before the bullet leaves the barrel, which pushes the barrel slightly upward in your hand. The effect is less and less noticeable with heavier and heavier revolvers. Naturally.

This can often be verified with many revolvers by laying the revolver down on its sights and you will see this effect because now the barrel points upward. It's hard to see this with most autos since the barrel is covered up.

What?!?!? Recoil starts to occur before the bullet leaves the barrel? ! ?

Ayup. Look at the physics involved.

See Hatcher's Notebook in the "Theory of Recoil" section. Arithmetic-heavy but still readable.

Hatcher is sort of the "Sir Isaac Newton" with respect to gun physics. He should have called [i[Hatcher's Notebook[/i], "Hatcher's Principia."

Terry, 230RN

REF (Principia):
https://en.wikipedia.org/wiki/Philosophiæ_Naturalis_Principia_Mathematica

"Philosophiæ Naturalis Principia Mathematica (English: The Mathematical Principles of Natural Philosophy)[1] often referred to as simply the Principia , ...is a book by Isaac Newton that expounds Newton's laws of motion and his law of universal gravitation."

 

[Mark_Mark]

Any object in deep space will fall to somewhere if it is has no velocity. There is gravity everywhere in space. I am not aware of any object in space that has no velocity. There are a bazillion objects that are orbiting about other objects, but they all are falling. It is just that the centrifugal force makes them appear to not be falling. If their velocity were to stop, the fall would happen immediately.

well there is the Great Void with nearly nothing the we can see. That would be a great candidate for no gravity testing.

 

[Jim Watson]

Did they do it with a smooth or rifled bore?

1911 in a Ransom Rest, hence my comment and why they were likely out of simultaneity by 39 milliseconds.

SF Sidebar:

The average gravitational acceleration on earth (g) is g = 9.8 m/s^2 (meters per second per second)

David Weber will really mess with your math in the Honor Harrington stories, sometimes he gives spaceship acceleration in gees, sometimes in km/sec^2. Two different numbers.

Poul Anderson once had a spacefaring character suggest that the standard be changed, defining a gee as 10 m/s^2 and Earth gravity of .98 G.

There are a bazillion objects that are orbiting about other objects, but they all are falling.

Heinlein therefore referred to the state of operations in orbit or in unpowered trajectory as "free fall." Now we have to get precious and say "microgravity."

 

[jmorris]

I would think it doesn't matter, but they used a 1911.

I would think an unstable projectile would have a lot more drag.

 

[Hugger-4641]

I would think an unstable projectile would have a lot more drag.

It would, but that still wouldn't affect how long it took to drop, would only affect the distance it traveled before hitting ground.

 

[Riomouse911]

I have a Ross M-10 sporter in .280 ross, an early really high velocity ( relative to the times ) cartridge. The rear sight has one flip up leaf that is marked 0-500. I have heard that back then they thought a high velocity bullet didn't start to drop until it slowed down considerably, which, of course, isn't true. If you fire any rifle exactly parallel to the ground, and drop an identical bullet (only) from your hand at the same height at the same time, they will both hit the ground at the same time.

Exactly. One will land at your feet and the other will land some distance away at the same time the first one lands…provided the area where the shooter fires is nice and flat. Ol’ Sir Isaac was pretty darn sharp!

I’ve had to explain trajectory to attorneys several times; some get it, some don’t.

Stay safe.

 

[230RN]

Double post. Please delete.

 

[Mal H]

well there is the Great Void with nearly nothing the we can see

What and where is this "Great Void" of which you speak?

That would be a great candidate for no gravity testing.

That idea is somewhat of a Catch-22. Everything in the universe with the possible exception of photons has gravity more or less, and even photons are affected by gravity. So if you attempt any experiment in an area where there is no gravity (which is impossible, but we'll say it is possible for the sake of this discussion), then you and/or any instrument or mechanism you use to test the no-gravity effects will bring gravity into the neighborhood of the experiment.

 

[230RN]

^ Yes.

 

[ericuda]

Better change title of thread. Sure lots of posts that are clearly not dummies. Good fun thread.

 

[Elkins45]

Former physics teacher here. There’s a fairly easy experiment you can do that only requires two coins, a ruler and the edge of a table. It flings one coin horizontally while dropping the other so you can observe them hit the floor at the same time. Kids had a hard time believing a bullet fired from a gun falls at the same rate as one dropped but this helped convince many of them.

Found it described here: https://sciensation.org/hands-on_experiments/e5060p_fallingCoins.html

 

[Mark_Mark]

What and where is this "Great Void" of which you speak?


That idea is somewhat of a Catch-22. Everything in the universe with the possible exception of photons has gravity more or less, and even photons are affected by gravity. So if you attempt any experiment in an area where there is no gravity (which is impossible, but we'll say it is possible for the sake of this discussion), then you and/or any instrument or mechanism you use to test the no-gravity effects will bring gravity into the neighborhood of the experiment.

it a strange place in the universe, with a span of 1.8 billion light years of nothing. Recently discovered place

 

[film495]

9.8 m/s2 .. meters per second squared, so - if you know the weight of any object, in theory anyways, you can just do a formula to see how far it falls in a given time because of gravity acting up on it.

 

[Mark_Mark]

then you and/or any instrument or mechanism you use to test the no-gravity effects will bring gravity into the neighborhood of the experiment.

Great point!!!

Matter does act different when being recorded or measured or observed.
https://www.sciencedaily.com/releases/1998/02/980227055013.htm

 

[Mal H]

it a strange place in the universe, with a span of 1.8 billion light years of nothing. Recently discovered place

We are really getting off the original topic, but I guess it still involves gravity so here we go.

The image on the left of your post looks exactly like a large dust cloud in our own galaxy. I'm fairly certain that is what it is.

The CMB (upper right image) does have many "voids" in it. But you have to understand that what is called a void isn't truly devoid of all matter. The dark regions are simply colder regions of matter measured in micro-Kelvins. All of space has some matter in every cubic kilometer. The void you are talking about is in line with the Great Cold Spot in the CMB. I'll bet there is still many, many stellar masses of matter in that void, but it is so large and the mass is so dispersed that it appears to be non-existent.

 

[ericuda]

The op wanted to explain how bullet drops and it is complicated but easily explained with physics. Shoot 1 at 3000 fps, just drop other and hits ground at same time. Truly amazing we are discussing 200 year old physics.

 

[Mal H]

Honestly, I think we're done here. I'm as guilty as anyone else in taking the discussion too far afield (by billions of light years ).

I'm sure Hugger-4641 has plenty of ammunition, so to speak, to eddycate his friend - closed.