Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.
Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.
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Hello everyone, been away for away but i've got a good one for you
Assuming that the earth is a perfect sphere, if you took a belt and wrapped it perfectly round the earth (once) it would be the same value as the circumfrance of the earth. Now if you increased the length of the belt by 1 metre and pulled it taught, how high above the surface of the earth would the belt be?
(also assuming the belt has not elastic properties)
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How is the radius of a circle related to the circle’s circumference? How much must the radius be increased to produce a 1-meter change in the circumference?
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Im not entirely sure i understand why your confused but here are the values for the earth.
Radius = 3963 miles or 6 377 830.27 meters ( if you prefere S.I Units)
Circumference = 24900.26 miles or 40 073 084 meters
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Mitchy T wrote:
Im not entirely sure i understand why your confused ...
I’m not confused, Mitchy. I was simply responding to your “Brain Teaser.”
PS: You really should pay more attention to your grammar and punctuation.
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Ok fair enough, I simply couldn't understand why you answered my question with two other questions. I have the proof to the answer of the "brain teaser" and nowhere could I deduce where your answers were coming from
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You can compare the area of the the circle enclosed in both cases, find the difference and divide by the circumference of the circle midway between the two.
so how do you solve this problem
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Maybe 1/(2*Pi) m?
Last edited by Bob Nob (2007-03-30 13:09:05)
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Hello physicists.
The belt is pulled taut, not to mention held there by gravity.
The only place the belt and Earth may be apart is where they're being tensioned, separated by either clasp if broken or a loop of anywhere up to almost half a meter of the belt's material if continuous.
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I'm glad this one was pulled from the ashes. I recently worked this one out because it was a question our math department here at Longwood University posed as their monthly brain teaser. You have to solve a transendental equation to get the answer.
I checked my math three or four times, since I was surprised by the answer. You could easily ride an elephant under the string.
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