Does a RB travel with constant rotation, or accelerate?

[TomV]

Reminds me of Einstein's thought experiment that Hawking talked about in 'A Brief History of Time':

A man bounces a ball on a flatcar on a moving train. To him the ball is bouncing straight up and down. Another man is standing beside the tracks and watches the man bouncing the ball as he goes by. To him the ball is flying in a long arc. Both things are true. The ball IS bouncing straight up and down, and it IS bouncing in an arc. All depends on your frame of reference....

Correct. View point is the key always.

 

[Carbon 6]

Any way you slice it then, you don't have to duck when firing straight in the air.

Don't bend over too far when you duck , blood might rush to your your head and make you dizzy.

 

[Carbon 6]

Also, and maybe most importantly, the inertia affecting the ball, as it is traveling the same speed as the earth and wants to continue so. Like throwing something out the car window. So there is that.

Your presumption here is also incorrect.

 

[Gun Tramp]

Like throwing something out the car window.

I once threw up out of a car window.

 

[hawkeye2]

I once threw up out of a car window.

I hope you were looking back when you did.

 

[bisleyjohn]

All this discussion, hours of trigger time being lost. You should all know that every ball or bullet you load will go not where you want it to but exactly where it wants to go.

 

[Zonie]

Also, and maybe most importantly, the inertia affecting the ball, as it is traveling the same speed as the earth and wants to continue so. Like throwing something out the car window. So there is that.

Your presumption here is also incorrect.

No. You saying his presumption is incorrect is, incorrect.

If you are riding in a car at 60 miles an hour and you shoot a bullet at 900 feet per second out the side window of the car the bullet will have a forward velocity relative to the road of 60 mph (88 feet per second) and a lateral velocity relative to the road of 900 feet per second.
If there was nothing to slow the bullet down (like wind resistance), the bullet would strike whatever it hits with a velocity greater than 900 fps because of the additional forward motion in the direction of the road. (This gets into vectors and all of our mathematics hating people will scream and run away if we start talking about those.)

 

[rdlowe]

Suppose you’re in a canoe that’s crossing a river flowing at 5 m/s and you can row at 2 m/s and...wait, that would be a terrible day to go canoeing.

 

[tenngun]

So now the question is: as your moving down stream at 3m/sec will you spin at a constant rate if you stop paddeling?

 

[Carbon 6]

No. You saying his presumption is incorrect is, incorrect.

If you are riding in a car at 60 miles an hour and you shoot a bullet at 900 feet per second out the side window of the car the bullet will have a forward velocity relative to the road of 60 mph (88 feet per second) and a lateral velocity relative to the road of 900 feet per second.
If there was nothing to slow the bullet down (like wind resistance), the bullet would strike whatever it hits with a velocity greater than 900 fps because of the additional forward motion in the direction of the road. (This gets into vectors and all of our mathematics hating people will scream and run away if we start talking about those.)

How does that relate to what he quoted ?

Does a RB travel with constant rotation, or accelerate?

It may be true but it's not relevant. Therefore, it's incorrect.

It's like asking the question what color is that house? and answering my dog is brown.
Sure, your dog is brown but it has nothing to do with the question.

 

[TomV]

Once leaving the barrel there are no forces remaining in the direction fired to accelerate the ball in flight, it only slows from air resistance and falls due to gravity. Rotational spin is being resisted by air and the surface of the rb that is neither round or smooth due to the lands and grooves of the barrel and abuse of being loaded and fired. Only in vacuum of space could is remain constant if absent of gravity or solar wind effects.

 

[nkbj]

You know, some day muzzleloaders are going to have to do this all over again because there's no air on The Moon; smoothie shooters are gonna be ecstatic.

 

[TomV]

Exactly, maybe no Newtons laws of physics will apply.

 

[rdlowe]

So now the question is: as your moving down stream at 3m/sec will you spin at a constant rate if you stop paddeling?

Yes, this happened to my good friends Marshall, Will and Holly, on a routine expedition.

 

[Tanglefoot]

Larry's original question was:
Here is the question: Does the RB continue rotation of 1 turn every 4', or does it accelerate to a faster rotation?
The answer is: NO.

 

[TomV]

Not only does it not accelerate in rotational rate it declines.

 

[hawkeye2]

Larry's original question was:
Here is the question: Does the RB continue rotation of 1 turn every 4', or does it accelerate to a faster rotation?
The answer is: NO.

The answer is NO and NO!

 

[TomV]

Accelerating defies logic, it begins slowing the moment it leaves the muzzle until gravity ends its flight.

 

[Cobra6]

If you are riding in a car at 60 miles an hour and you shoot a bullet at 900 feet per second out the side window of the car the bullet will have a forward velocity relative to the road of 60 mph (88 feet per second) and a lateral velocity relative to the road of 900 feet per second.

Now you can imagine how difficult it was to put steel on target from a helicopter gunship. And doing that with no really accurate fixed sights.

In a Charlie model gunship we had [in most configurations] two seven shot rocket pods for the 2.75 inch rockets. There was no sighting station for fixing targets and the rockets were adjusted for 1200 meters. They were shot instinctively. Sometimes the co-pilot and pilot would use ice cream sticks or a grease pencil + marked on the windshield to aim the rockets. Other pilots did not use them.

The crew chief and gunner had [and again in most configurations] the M-23 system which shot suppressive fire out the side of the aircraft. Excepting the M60 sights the crew had to calculate where the rounds would suppress based on the A/C speed, A/C bank [and rate of bank,] type of target and how far away were we from the engagement area. A stationary enemy 51 Cal position is a lot different than enemy troops on the run. For example, if a crewmember was firing at a bunker traveling from right of target to left of target, the gunner would fire to the right of target and adjust lead into the bunker. If the A/C was firing at that same target in a hard left bank the gunner would fire low and to the right of target.

In 1969 we transitioned from the "C" Model gunships to the AH-1G. I never had a full appreciation for the gunners target acquisition skills on the antiquated "C" Model gunships until I had to fire the front turret on the AH-1G. The turret consisted of the 40mm cannon and the 7.62 cal mini-gun. The AH-1G did have a sighting rail system for firing both the 40 and mini. However, the system was "just OK" and never really worked except to get the rounds close to target and the co-pilot had to walk the rounds in closer. But again, shooting out the side or adjacent to the forward velocity of the A/C relative to the target was at first very difficult. Also, take into consideration the very low velocity of the 40 which was a thumper, very slow. To engage a target in the scenario above with the 40mm, going from left to right, the co-pilot had to adjust for all the physics variables and speed of the projectile.

I once threw up out of a car window.

Did you know that it's a lot easier to throw-up out of a "C" model gunship without doors than an AH-1G with a canopy. Thought I'd mention it.


Cobra 6

 

[Zonie]

I think we ought to stick to muzzleloaders rather than those modern thingies. I'm only leaving it here because it demonstrates the fact that things that are moving in one direction, stay moving in that direction while they may be moving at the same time in another direction.