document.write( "Question 1188509: A ball is thrown vertically upward from the top of a building 64 feet tall with an initial velocity of 48 feet per second. The distances (in feet) of the ball from the ground
\n" ); document.write( "after t seconds is s(t) = 64 + 48t - 1612.
\n" ); document.write( "(a) After how many seconds does the ball strike the ground?
\n" ); document.write( "(b) After how many seconds will the ball pass the top of the building on its way down? \n" ); document.write( "
Algebra.Com's Answer #819621 by ikleyn(52811)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "A ball is thrown vertically upward from the top of a building 64 feet tall with an initial velocity of 48 feet per second.
\n" ); document.write( "The distances (in feet) of the ball from the ground
\n" ); document.write( "after t seconds is s(t) = 64 + 48t - \"cross%281612%29\" 16t^2.
\n" ); document.write( "(a) After how many seconds does the ball strike the ground?
\n" ); document.write( "(b) After how many seconds will the ball pass the top of the building on its way down?
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document.write( "(a)  To answer question (a), solve this equation\r\n" );
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document.write( "         -16t^2 + 48t + 64 = 0      (ground level)\r\n" );
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document.write( "     First, simplify it by dividing both sides by -16\r\n" );
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document.write( "          t^2 - 3t - 4 = 0.\r\n" );
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document.write( "     To solve it, factor left side\r\n" );
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document.write( "          (t-4)*(t+1) = 0.\r\n" );
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document.write( "      Of two roots,  t= 4  and  t= -1,  use only positive one  t= 4  seconds.     ANSWER\r\n" );
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document.write( "(b)  To answer question (b), solve this equation\r\n" );
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document.write( "         -16t^2 + 48t + 64 = 64      (top of the building level)\r\n" );
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document.write( "     Simplify it\r\n" );
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document.write( "         -16t^2 + 48t = 0\r\n" );
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document.write( "         -16t(t - 3) = 0.\r\n" );
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document.write( "      Of two roots,  t= 0  and  t= 3,  only greater value t= 3 seconds is the solution to this part of the problem.\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
\n" ); document.write( "\n" ); document.write( "    - Problem on a toy rocket launched vertically up from a tall platform\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.
\n" ); document.write( "Read them attentively and learn how to solve this type of problems once and for all.\r
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\n" ); document.write( "\n" ); document.write( "Also,  you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the topic \"Projectiles launched/thrown and moving vertically up and dawn\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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