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Air resistance is well known in skydiving. Eventually, air resistance will cancel out gravity, you stop accelerating, and you'll reach what's called terminal velocity, the maximum speed you'll reach when falling down.
Obviously, if there's a force countering gravity (ie: air resistance), then there's an obvious effect, since Newton's law states:
the velocity of an object moving in a given direction will remain constant provided there are no forces acting in that direction.
Air resistance is well known in skydiving. Eventually, air resistance will cancel out gravity, you stop accelerating, and you'll reach what's called terminal velocity, the maximum speed you'll reach when falling down.
Things moving in the air are constantly colliding with air molecules as well as creating patterns of flow around the objects. I thought people understood this. And the faster you go, the more frequently the object runs into air.
Terminal Velocity? Anyone?
Holy Nono beat me to the punch... People do read.
I always hated physics in high school, tbh
What?
How come gliders can be yanked off the ground by a powered plane?
Have you heard of the cambered wing?
Take a piece of paper and blow across the top of it while holding it and tell me why it rises while air is clearly flowing over the top.
Seriously CC I have questions as you apparently have shot way more than I have. I would appreciate knowing more about methods to prevent big kickbacks.
Last edited by pgardn; 01-26-2015 at 06:03 PM.
I did to.
There are several ways. Easiest is mass of the rifle. My sniper rifle (very much like the one in the movie) weighs 9 pounds less scope. Increasing mass of the rifle decreases felt recoil.
Then there are muzzle breaks. All of the powder is never used. A muzzle break has holes/slots which channel the remaining gas after the projectile has left the barrel out to the sides and up instead of continuing to provide straight line thrust off the end of the barrel. They are loud, but again, suppress felt recoil.
The most complicated are the spring assisted recoil dampeners like the Barrett .50. The barrel itself recoils back against springs which soften the perceived recoil.
We are talking about a bullet here, guys....not a skydiver. Air resistance is mathematically there but for practical purpose in this discussion it is negligible.
And the glider analogy is stupid. It is not a projectile. A sailplane trades al ude for speed of air over the wing that provides lift which keeps it from dropping like a piano. A sailplane is always losing al ude (traded for speed/lift) unless it in a column or wave of air that is rising faster than the al ude surrendered for lift.
Aha!
Those tanks with those strange muzzles. I was trying to figure that out. I thought it may have something to do with heat but that makes way more sense.
So shotguns used to shoot big birds ( geese I guess) at distance (requiring velocity) You gotta aim up. And they send up a lot of shot. Everything points to That's gotta hurt? Springs or what? Just really heavy?
Yeah, a 3 1/2" high brass 12 gauge goose or buckshot load is gonna thump you. A gas operated semi-auto which uses part of the expended gas to cycle the action won't kick as hard as an over/under all other things being equal.
In physics those are projectiles. The analogy is used only to show how important air can be. Bullets obviously have a much smaller surface area and are much denser. But if you could make a round hollow bullet with some light tough alloy and then make more friction on the top of the barrel compared to the bottom(or some other way of getting big underspin) I bettin you could get some rise.
Sorry.
What does cycle the action mean?
back to the sailplane analogy...If you pay attention to ulus clouds they are constantly forming and breaking up and new clouds form. When a cloud is forming it sucks warm air up the center which reaches the "top" and cools and spills back out and down because cold air is heavier than warm air.. In Texas when we fly sailplanes we use these forming clouds to find our rising column of air...I have been in rising columns as fast as 800 feet per minute...then as the cloud peters out we scoot to the next one trading al ude for speed to get there....For example, the best glide ratio for a Sweizer 2-33 is at 50mph where you trade one foot of al ude for 23 feet forward...I've been as high as 10,000 feet on a 1800 foot drop with a perfect day of continuously finding and using the updraft in forming clouds....
The gases throw the bolt back, ejecting the spent hull, and load the next s . When you see the guys in the movies firing on full auto and the spent brass is spilling out the side that is the action "cycling" between every shot.
Then you are Frggn brave.
No I get it. The hang gliders work on those concepts as well.
Just saying wings are used in aircraft for more than stabilizing or a push from underneath from up drafts.
Getting accelerated up like that... I could not handle that. I could on a ride, but not out on my own. Instant panic.
Thats nuts. I have a youngun.
I had no idea.
Very cool. Really probably very hot.
This is debatable....I don't want to get in a pissing contest with you. I agree with a lot of things you've said....but I've heard that some bullets rise when they leave the barrel. The velocity, change in pressure at the end of the barrel, and the shape of the bullet....causes some lift.
Again.....for the 3rd time. This is debatable. I'm not calling it fact....all I'm saying is some very knowledgeable people argue this. They (and me) maybe wrong.
BTW...the debate with you and cantthinkofanything....you are correct. As long as the bullet is released from rest (well....the bullet has no additional force added in the vertical direction....i.e. the guy isn't throwing the bullet downward) it will hit the ground at the same exact time as a bullet fired horizontally from the barrell. The only acting vertical component is gravity. And it will be a constant 9.81 m/s^2 for both projectiles. The same thing with the baseball.....as long as the baseball is not thrown downward...the time will be the same.
I didn't take physics in high school but I was unfortunate enough to take Physics I, II, and III in college. Physics I wasn't bad (BTW...my teacher was awesome...that might have been the reason I think it wasn't that bad)....but Physics II and III sucked ass. Electricity is a tricky concept to grab for some (especially me). Glad I went the civil engineering route....instead of the electrical engineering route.
All I want to know about electricity is when I flip the switch on my wall....the light should come on. And if it doesn't, It means I haven't paid my electricity bill
Yep. The electrical physics was hard to wrap my head around but once it started sinking in it made chemistry start to make sense.
I didn't take physics in high school but I was unfortunate enough to take Physics I, II, and III in college. Physics I wasn't bad (BTW...my teacher was awesome...that might have been the reason I think it wasn't that bad)....but Physics II and III sucked ass. Electricity is a tricky concept to grab for some (especially me). Glad I went the civil engineering route....instead of the electrical engineering route.
All I want to know about electricity is when I flip the switch on my wall....the light should come on. And if it doesn't, It means I haven't paid my electricity bill
Eventually I had to learn the whole thing again on my own while writing/using physics engines.
I actually specialized in electronics in high school (we have some sort of vocational high schools down in ARG, that's what I did). I enjoyed that a little better, although with the advent of VHDL, it became sorta useless for system engineering.
CosmicCowboy
I just got off the phone with my father wishing him happy birthday. The reason why I bring this up is he knows more about weapons and bullets than any other man I've ever met in my life ( ...he owns a shooting range). And basically he agrees with you. So I'm willing to admit that I'm wrong.
He told me the whole bullet "rising" scenario....comes from the difference in sight level and bore level. The sight is actually angled slightly downward....and the bore level is perfectly horizontal. The bullet rises only in relationship with the sight level. At some point the two paths (sight level and bore level) intersect. This is where you are zeroed at.
But even my father....says that he hears this debate all the time at his shooting range.
From a physics point of view, it's possible. I really have no doubt. Now if guns shooting projectiles are ever made this way is a whole different debate. I have never heard of a gun made for this purpose. And I don't know that much about guns. I do know the physics though. There are too many other projectiles that do rise hit horizontally. I have seen it done in a number of situations. Most easily observed is a ping pong ball stuck on the bottom half exiting off a horizontal or even slanted down table slick table. Give it enough underspin and it will rise.
Electricity got me interested in physics. The first time I saw a galvanometer needle deflect while a wire was moved between two magnets I totally freaked out. No batteries. No Fkn batteries needed to produce current. All toys had batteries yet no batteries needed. Then I was shown the little hand held generators that you turn hooked up to a little car with a little motor. And the damned car moved... Blew me away. Then turn the wheels of the car and the generator handle turned, are you Fkn kidding!
Eventually I had to learn the whole thing again on my own while writing/using physics engines.
I actually specialized in electronics in high school (we have some sort of vocational high schools down in ARG, that's what I did). I enjoyed that a little better, although with the advent of VHDL, it became sorta useless for system engineering.
God Bless Michael Faraday.
Yes, it's a in college.
Holy crap! I'm surprised CC didn't need to explain the need for a gun to accurately fire a bullet.
Just wondering what rifle anyone would use that would provide topspin?
I did find this and they are projectiles but I don't know how they work.
http://www.newsmax.com/Newsfront/mil.../15/id/613048/
Im gonna guess they can change the shape thus air flow.
And I don't know if this site is a pile o crap.
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