document.write( "Question 1033304: a body falls freely from the top of the toeer and during last second of the fall ,it falls through 25m.Find the height of tower. \n" ); document.write( "

Algebra.Com's Answer #647945 by ikleyn(52790) $\"\"$ $\"About$

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\n" ); document.write( "A body falls freely from the top of the tower and during last second of the fall, it falls through 25 m. Find the height of tower.
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document.write( "This fact is known very well from Physics, or from Calculus or from . . . \r\n" );
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document.write( "   Free falling body falls the distance  in t seconds, where \"g\" is the gravity acceleration.\r\n" );
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document.write( "Therefore, your equation to find the time is \r\n" );
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document.write( "   -  = 25.\r\n" );
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document.write( "In this problem, take g = 10   (actually, g = 9.81 ). You will get\r\n" );
document.write( " -  = 25,  or\r\n" );
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document.write( " = 25,  or\r\n" );
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document.write( " = 25,   or\r\n" );
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document.write( "10t = 30.\r\n" );
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document.write( "Hence, t = 3 seconds.\r\n" );
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document.write( "For 3 seconds, the body falls  =  = 5*9 = 45 m.\r\n" );
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document.write( "Answer. The height of the building is 45 m.\r\n" );
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document.write( "Calculate the distances the free falling body falls during the 1-st, 2-nd, 3-rd . . . seconds. Use g = 10 .\r\n" );
document.write( "1-st sec.:   =  = 5 m.\r\n" );
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document.write( "2-nd sec.:   =  = 20-5 = 15 m.\r\n" );
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document.write( "3-rd sec.:   =  = 45-20 = 25 m.\r\n" );
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document.write( "See these numbers: 5, 15, 25 . . . \r\n" );
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document.write( "They form ARITHMETIC PROGRESSION !!!\r\n" );
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document.write( "This remarkable fact is general:\r\n" );
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document.write( "   The distances that the free falling body falls during the first second, \r\n" );
document.write( "       the next one, the third and so on, form the arithmetic progression.\r\n" );
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document.write( "Miracle ?!  - No, the algebra only. - See the lessons \r\n" );
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document.write( "   Free fall and arithmetic progressions\r\n" );
document.write( "   Uniformly accelerated motions and arithmetic progressions\r\n" );
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document.write( "in this site.\r\n" );
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document.write( "And not to forget, the calculations above that lead to the number \"25 m in third second\" give another solution to the original problem.\r\n" );
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