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### Needle problem simulation (Geometric distirbution)

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```Hello,

Is there already existing matlab code that solves the following problem.

1) choose random points as targets on the floor (say living room in house).
2) Person stands near those points and drops the needle pin.
3) We want to show that where the needle falls (closer to the random points).

thanks and Regards
R
```
 0

```"Ram Lakshmi" <ram.gopal@nsn.com> wrote in message
news:hijit0\$s7o\$1@fred.mathworks.com...
> Hello,
>
> Is there already existing matlab code that solves the following problem.
>
> 1) choose random points as targets on the floor (say living room in
> house).
> 2) Person stands near those points and drops the needle pin.
> 3) We want to show that where the needle falls (closer to the random
> points).

I doubt it.  You haven't said anything about how you want to "show that
where the needle falls" -- what model are you using to simulate the falling
needle?  Are you taking into account wind resistance (it's small, but so is
a needle.)  Are you assuming the needle falls point-first or do you take
into account the possibility that the person dropping the needle spins it as
they drop it so it tumbles and rotates in the air?  Are you treating the
mass of the needle as being uniformly distributed or do you take into
account the fact that the eye of the needle bulges out and probably impacts
the center of mass?  You also haven't clarified exactly what type of needle,
now that I think about it -- the result of the simulation would be much
different if you're dropping sewing needles (as I've been assuming):

http://en.wikipedia.org/wiki/Sewing_needle

than if you're dropping knitting needles:

http://en.wikipedia.org/wiki/Knitting_needle

or a hypodermic needle:

http://en.wikipedia.org/wiki/Hypodermic_needle

or the Space Needle:

http://en.wikipedia.org/wiki/Space_Needle

If you need help in solving this problem, write out what assumptions you're
making and what model you're using, show what you've done to try to solve

--
Steve Lord
slord@mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ

```
 0
Reply slord (13361) 1/13/2010 2:54:58 PM

```I first thought of Buffon's Needle - a famous problem in statistics
which can be solved analytically or via a Monte Carlo Approach.  It's
a well known homework problem.
http://en.wikipedia.org/wiki/Buffon%27s_needle
```
 0
Reply imageanalyst (7596) 1/13/2010 3:53:25 PM

```"ImageAnalyst" <imageanalyst@mailinator.com> wrote in message
>I first thought of Buffon's Needle - a famous problem in statistics
> which can be solved analytically or via a Monte Carlo Approach.  It's
> a well known homework problem.
> http://en.wikipedia.org/wiki/Buffon%27s_needle

That was my first thought to, but usually when someone describes Buffon's
Needle they mention the lines on the surface on which they drop the needle.
The OP's message didn't mention any lines.

From the original description, it sounded like maybe the OP was trying to
model that old Sprint commercial:

--
Steve Lord
slord@mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ

```
 0
Reply slord (13361) 1/14/2010 2:50:33 PM

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