document.write( "Question 46407: the period of a simple pendulum is directly proportional to the square root of its length. If a pendulum has a length of 6 feet and a period of 2 seconds, to what length should it be shortened to achieve a 1 second period?\r
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Algebra.Com's Answer #30765 by Earlsdon(6294)\"\" \"About 
You can put this solution on YOUR website!
You can start by writing the equation of proportionality:
\n" ); document.write( "\"P+=+k%2Asqrt%28L%29\" Where: P = period, L = Length, and k is the constant of proportionality.
\n" ); document.write( "We need to find the value of k. We can do this by substituting the given values of L (6 ft) and P (2 secs) into the above formula and solving for k.\r
\n" ); document.write( "\n" ); document.write( "\"2+=+k%2Asqrt%286%29\" Divide both sides by \"sqrt%286%29\"
\n" ); document.write( "\"k+=+2%2Fsqrt%286%29\"\r
\n" ); document.write( "\n" ); document.write( "Now the formula for the period is:
\n" ); document.write( "\"P+=+%282%2Fsqrt%286%29%29sqrt%28L%29\"\r
\n" ); document.write( "\n" ); document.write( "To answer your probem however, we need to solve this equation for L.
\n" ); document.write( "\"P+=+%282%2Fsqrt%286%29%29sqrt%28L%29\" Multiply both sides by \"sqrt%286%29\" and divide by 2.
\n" ); document.write( "\"sqrt%286%29P%2F2+=+sqrt%28L%29\" Now square both sides.
\n" ); document.write( "\"%286%2F4%29P%5E2+=+L\" Simplify.
\n" ); document.write( "\"L+=+%283%2F2%29P%5E2\"\r
\n" ); document.write( "\n" ); document.write( "Now we can answer your problem. What should L be if P is to be 1 second.
\n" ); document.write( "Just substitute P = 1 into the above equation and solve for L.
\n" ); document.write( "\"L+=+%283%2F2%29%281%5E2%29\"
\n" ); document.write( "\"L+=+3%2F2\"
\n" ); document.write( "\"L+=+1.5\"ft.
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