Speed vs. cast

kawika b · May 26, 2012, 08:05:00 PM

Is it me or is the question being overcomplicated?

atatarpm · May 26, 2012, 08:48:00 PM

Ok I am lost I thought cast came from the limbs abblity to transfer energy to the arrow which then will results in speed which then will result in penitration when the arrow comes to a stop. Or maybe I am wrong :confused:

khardrunner · May 26, 2012, 10:16:00 PM

Yikes!!!! Guys once the arrow leaves the bow it is a projectile on which the only forces acting on it are friction (air) and gravity. If the arrow is aerodynamically the same then friction can be neglected (same coefficient of kinetic friction). Gravity works on all masses equally as well NOT more on heavier masses... Which is why all objects fall at the same rate in a vacuum.

This means that the only thing that will determine the cast is in fact the initial velocity and angle at which the arrow is launched. The reason heavier arrows drop off more quickly is because thier initial velocity is less (f=ma).

All that to say physics (representing natural law) dictates that the faster arrow travels further thus has greater cast all other factors bein equal. Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case!

khardrunner · May 26, 2012, 10:18:00 PM

Sorry for the typos i did this on my phone past my bed time

Killdeer · May 27, 2012, 08:39:00 AM

My brain hurts!

Killdeer the mathematically challenged

owlbait · May 27, 2012, 08:47:00 AM

I'm with you Killie! I thought maybe foc, efoc, etc. might have some influence on cast. Same weight arrow, leaving the bow, different results. And THEN.... "My bow really likes a heavy arrow" thrown into the equation. :D

Raging Water · May 27, 2012, 09:44:00 AM

All that to say physics (representing natural law) dictates that the faster arrow travels further thus has greater cast all other factors bein equal. Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case

UH? I don't understand this part. I can't throw a bowling ball as far as I can throw a baseball.

So, what am I missing here?

Signed, Confused in Texas

Bear Heart · May 27, 2012, 10:56:00 AM

QuoteOriginally posted by Raging Water:
All that to say physics (representing natural law) dictates that the faster arrow travels further thus has greater cast all other factors bein equal. Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case

UH? I don't understand this part. I can't throw a bowling ball as far as I can throw a baseball.

So, what am I missing here?

Signed, Confused in Texas

That is because you don't have the strength to get to bowling ball up to the speed of the baseball.

khardrunner · May 27, 2012, 01:03:00 PM

Whups double post

khardrunner · May 27, 2012, 01:03:00 PM

Exactly. Its all about initial velocity and angle of launch. A bowling ball is more massive than a baseball so if you apply equal force to them both the baseball will be moving faster when you release. This means it will go further. Once you release though you are no longer imparting any force. Only gravity and air resistance work to slow the balls down. Interestingly enough, if they are the same size they will slow down at the same rate

eminart · May 27, 2012, 01:08:00 PM

I'm probably dumb, but, if cast is how far a bow will shoot, and speed is how fast it will shoot, then I don't think you can have one without the other.

If you throw a ball "fast" it will go farther than if you throw it slow - every time. If you throw a ball far, it it will go faster than a ball thrown not so far - every time.

Bladepeek · May 27, 2012, 01:16:00 PM

QuoteOriginally posted by John Havard:
32 fps/second is an immutable fact that can't be gotten around.

I agree that's a fact of physics, so why is it not helping me any more when I try to accelerate down to tie my shoes? Oh yeah, that mass in the middle wants to stay at rest.

khardrunner · May 27, 2012, 01:24:00 PM

God bless newton!!

kawika b · May 27, 2012, 02:37:00 PM

QuoteOriginally posted by Bladepeek:
I agree that's a fact of physics, so why is it not helping me any more when I try to accelerate down to tie my shoes? Oh yeah, that mass in the middle wants to stay at rest.

Oh man I SO resemble that remark.

Raging Water · May 27, 2012, 04:31:00 PM

QuoteOriginally posted by Bear Heart:

QuoteOriginally posted by Raging Water:
All that to say physics (representing natural law) dictates that the faster arrow travels further thus has greater cast all other factors bein equal. Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case

UH? I don't understand this part. I can't throw a bowling ball as far as I can throw a baseball.

So, what am I missing here?

Signed, Confused in Texas
That is because you don't have the strength to get to bowling ball up to the
speed of the baseball. [/b]

But the quote said:

Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of
launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case

So, is the assumption that the 1,000 gr arrow is being shot out of a heavier draw weight bow, than the 500 gr arrow?

Or, are both arrows being shot out of the same bow?

khardrunner · May 27, 2012, 04:41:00 PM

It would be a bow that would get it to the same initial velocity as the 500 grn arrow out of its bow

Kevin Dill · May 28, 2012, 06:09:00 AM

None of this really matters....if you hit the dreaded "void".

pdk25 · May 28, 2012, 11:21:00 AM

QuoteOriginally posted by Raging Water:

QuoteOriginally posted by Bear Heart:

QuoteOriginally posted by Raging Water:
All that to say physics (representing natural law) dictates that the faster arrow travels further thus has greater cast all other factors bein equal. Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case

UH? I don't understand this part. I can't throw a bowling ball as far as I can throw a baseball.

So, what am I missing here?

Signed, Confused in Texas
That is because you don't have the strength to get to bowling ball up to the
speed of the baseball. [/b]
But the quote said:

Also a 1000 grn arrow will travel EXACTLY the same distance as a 500 grn arrow if all other factors ( includin angle of
launch, initial velocity, and coefficient of friction etc) are the same. Mass doesnt matter in this case

So, is the assumption that the 1,000 gr arrow is being shot out of a heavier draw weight bow, than the 500 gr arrow?

Or, are both arrows being shot out of the same bow? [/b]

Yes, Matt. The assumption is different bows. That is the only way to get the same velocity.

kawika b · May 28, 2012, 01:18:00 PM

The question was posed to differentiate cast and speed which was something of a debate in this thread http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=1;t=117016#000000

owlbait · May 28, 2012, 01:30:00 PM

Yep! Somewhere in the recesses of my bonehead I had this crazy vision that a bow could be made to cast an arrow a long distance, without regard to the speed. In other words, some bows are fast, some have great cast. I "tried" to make a (weak)connection that a flat bow would shoot flat(fast) whereas a long bow would shoot a long ways(cast). I must've failed my physics lesson on the day that was tested :D I'm glad that is now cleared up until some new materials and designs change the way we think.