document.write( "Question 1203448: A rock is thrown upward with a velocity of 14 meters per second from the top of a 35 meter high cliff, and it misses the cliff on the way back down. When will the rock be 3 meters from ground level? Round your answer to two decimal places.
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Algebra.Com's Answer #839024 by ikleyn(52908)\"\" \"About 
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\n" ); document.write( "A rock is thrown upward with a velocity of 14 meters per second from the top of a 35 meter high cliff,
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document.write( "The function describing the height over the base of the cliff is\r\n" );
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document.write( "    h(t) = -5t^2 + 14t + 35.\r\n" );
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document.write( "The rock will be 3 meters from ground level when h = 3.\r\n" );
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document.write( "So, to find the relevant time t, you should solve this equation\r\n" );
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document.write( "    -5t^2 + 14t + 35 = 3.\r\n" );
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document.write( "Simplify\r\n" );
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document.write( "    -5t^2 + 14t + 32 = 0\r\n" );
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document.write( "     5t^2 - 14t - 32 = 0\r\n" );
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document.write( "and find t using the quadratic formula\r\n" );
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document.write( "    t = \"%2814+%2B-+sqrt%28%28-14%29%5E2+-4%2A5%2A%28-32%29%29%29%2F%282%2A5%29\" = \"%2814+%2B-+28.91366459%29%2F10\".\r\n" );
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document.write( "Use the positive root and reject the negative one.\r\n" );
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document.write( "ANSWER.  t = \"%2814+%2B+28.91366459%29%2F10\" = 4.29 seconds  (rounded). \r\n" );
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\n" ); document.write( "\n" ); document.write( "In this site,  there is a bunch of lessons on a projectile thrown/shot/launched vertically up\r
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\n" ); document.write( "\n" ); document.write( "    - Introductory lesson on a projectile thrown-shot-launched vertically up \r
\n" ); document.write( "\n" ); document.write( "    - Problem on a projectile moving vertically up and down\r
\n" ); document.write( "\n" ); document.write( "    - Problem on an arrow shot vertically upward\r
\n" ); document.write( "\n" ); document.write( "    - Problem on a ball thrown vertically up from the top of a tower \r
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\n" ); document.write( "\n" ); document.write( "Consider these lessons as your textbook,  handbook,  tutorials and  (free of charge)  home teacher.
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