Visit the SWFA.com site to check out our current specials. |
To all the maths guru's |
Post Reply | Page <1234> |
Author | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
dsr
Optics Apprentice Joined: May/31/2007 Location: United States Status: Offline Points: 244 |
Post Options
Thanks(0)
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Trigger29,
Your statement is true that the bullet "sees" both components of drag. But for this problem it is proper to ignore the vertical segment of drag. Drag is a function of velocity squared . The vertical velocity is 13.86 ft/s at contact and assuming constant velocity for the horizontal component of 2850 ft/s. The squared velocities are 192 vs 8,122,500 respectively and the ratio is 0.0000236503 so it is safe to ignore the vertical air drag |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Kickboxer
MODERATOR Moderator Joined: February/13/2008 Status: Offline Points: 23679 |
Post Options
Thanks(0)
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Proof of -1 * x = -x, using simple math: Math fact: Any number times zero equals zero. 0 * x = 0 Now, zero can be written as (1 + -1) which follows from the definition of -1... -1 is the additive inverse of 1, ie., the number that when added to 1 give the additive identity element, 0. (1 + -1) * x = 0 Applying the distributive property: 1*x + -1*x = 0 (simplifying) 1x + -1x = 0, or x + -x = 0 (from the fact that 1 times any number is the same number), Which leads us to the fact that the number that when added to x gives us zero is -x, Therefore: -x = -1*x, We now use this theorem to prove that -1 * -1 equals 1: -1 * -1 = -(-1) = 1 This proof involves only simple elements of math, the associative and distributive properties and basic 1st year math facts. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Opinion,untempered by fact,is ignorance.
There are some who do not fear death... for they are more afraid of not really living |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dale Clifford
Optics Jedi Knight Joined: July/04/2004 Location: United States Status: Offline Points: 5087 |
Post Options
Thanks(0)
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
you used elements from ring theory in your proof, but didn't show that the basic assumptions were part of a larger group of sets having the same property (or lacking them)
0 * x = 0 is not a math fact -- it only applies to a certain group of rings, homomorism has not been established in your arguement (1+-1)*=0 you use the fundamental property of rings as a side note robertsons reference to topology above and the proof that the coffee cup is a doughnut can use a ring theory proof from cohomology of topological spaces. use of operations are illustrations of the proof , not a proof of it. example yes, we have no bananas a=1 b=1 if a and b are 2 positive numbers then -a and -b are negative numbers with product -a*-b=(-1*a)*(-1*b)=-1(a*b) a fundamental property of rings (yours above is the same, only more specic) minus a means not a minus minus a means not not a, which means yes a if you do not like this solution, I guess you think it is correct -a*-b=-1*a*-1*b=(-1)*(-1)*(a)*(b)=(-1)^2*a*b=1 but (-1)^2=-1
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
I love little league baseball-- it keeps the kids out of the house
Yogi Bera |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
preacherman
Optics Apprentice Joined: February/07/2012 Location: USA Status: Offline Points: 71 |
Post Options
Thanks(0)
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
go to hornady.com there you will find a ballistic calculator. Your BDC and bullet weight as well as humidity will effect the answer. First, is the bullet 30 cal? 338cal? 7mm? anyway you take your rifle standard range do the raw data then find your appropriate MOA in drop to the elevation.
there is your answer. If you want to be totally accurate anally so take into account the earths rotation at your co-ordinates. By the way if you drop a bullet from your bbl assuming this is an absolutely flat plane the same time elapses between the fired bullet and the dropped bullet. However there is no true flat plane on earth as it is an elongated sphere. Chuckle..... these things drive me nuts at ranges past 1000 yards. |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
men with guns who are free are called "citizens" without weapons they are called "subjects and or slaves"
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Kickboxer
MODERATOR Moderator Joined: February/13/2008 Status: Offline Points: 23679 |
Post Options
Thanks(0)
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dale, I found this for you...
Multiplication by 0, 1, 2 and 3
Multiplying by zero
|
Remember, multiplication by a whole number is REPEATED ADDITION.
|
Dale Clifford wrote: where do you think they get the rules of arithmetic--- the internet purplecow.math? every example you gave comes from operations in ring theory and set theory--- it takes priority
do you think the AMS (american math society) takes proofs from giraffemath?
I was suprized however that you didn't start with something like -- Let Z contain all the sets of real numbers--- your arguement (and the beginning ofmine) doesn't even rule out imaginary numbers or extent the rings to exponential functions.
basic math comes from group, and number theory please do a little more in depth |
Urimaginaryfrnd wrote: My bullet would travel all the way to the deer -- then it would hit the ground. |
dsr wrote:
What would hit the ground the bullet or the deer? And great now we get to fight over the variable "deer" ~ assume the deer is a sphere..... |
Alan Robertson wrote:
|
Oh boy! with a manifold --- hot gas --- internal
ballistics ---
I myself prefer
twister trousers (a type of manifold)
Dale Clifford wrote: The manifold and the deer/sphere analogy is really accurate. But its really a circle, sometimes with a bullseye on it. And the bench they shoot off is called a compacted stool. |
Being very politically incorrect the only thing I can think
to say to that is EX-LAX (see ICAO for
LAX)
Dale Clifford wrote: hope your talking about airports and not Lax algebras, giraffes are over my head |
The hyperbolic
nature of this thread leads us right back to here
Dale
Clifford wrote:
...AMS (american math society) takes proofs from giraffemath?
And without
further ado we leave the land of fruits and nuts. (Again being very politically incorrect)
Post Reply | Page <1234> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |