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[DPRG] Robot math problems

Subject: [DPRG] Robot math problems
From: R. Bickle rbickle at swbell.net
Date: Thu Feb 14 11:24:21 CST 2002

Simple Mike,

The Circumference of the spherical Earth is C = 2*pi*r

The difference in radii is: 12ft - 6ft = 6ft.

Adding to r yields: C = 2*pi*(r+6ft) --> c = (2*pi*r) + (2*pi*6ft)

The change in C is 2*pi*6ft = 37.7 feet.


-----Original Message-----
>From: dprglist-admin at dprg.org [mailto:dprglist-admin at dprg.org]On Behalf
Of Mike McCarty
Sent: Wednesday, February 13, 2002 2:07 PM
To: Clay Timmons
Cc: dprglist at dprg.org
Subject: Re: [DPRG] Robot math problems

On Wed, 13 Feb 2002, Clay Timmons wrote:

> Just working out a few robot navigation issues
> and thought I'd share a couple math problems
> I've encountered.  Have fun!  Took me about
> 10 minutes.

Really? Ten minutes? The first one is obvious, I thought. The other
took about 15 seconds of thought.

If these were posers, then how about this:

	A cable is being strung around the surface of the Earth at the
	equator at a height of 6 feet. After it is strung, the
	requirements change (don't they always?) and the cable must now
	be raised to 12 feet above the surface. How much additional
	cable must be inserted to raise the cable? (Assume the Earth is
	a perfect sphere.)

> If a 12" wide robot with 3" diameter wheels 
> has one wheel going 1/2 the speed of the other
> it will go in a circle.  
>    1) What diameter is that circle?
>    2) To make the robot go in a circle with 
>       a 9" radius on the inside wheel
>       what speed should the inside wheel
>       go as a percentage of the outside wheel?
> I have solutions and will post answers next week.


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