document.write( "Question 712033: an object is thrown upward from the top of a 144-foot building with a initial velocity of 128 feet per second. The height h of the object after t seconds is given by the quadratic equation h= -16t^(2)+128t+144. When will the object hit the ground? \n" ); document.write( "

Algebra.Com's Answer #437705 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
At $\"+t+=+0+\"$ ,
\n" ); document.write( " $\"+h%280%29+=+-16%2A0%5E2%2B128%2A0%2B144+\"$
\n" ); document.write( " $\"+h%280%29+=+144+\"$
\n" ); document.write( "which just means that the object is
\n" ); document.write( " $\"+144+\"$ ft above the ground
\n" ); document.write( "---------
\n" ); document.write( "When the object hits the ground, $\"+h+=+0+\"$
\n" ); document.write( " $\"+h+=+-16%2At%5E2%2B128t%2B144+\"$
\n" ); document.write( " $\"+0+=+-16%2At%5E2%2B128t%2B144+\"$
\n" ); document.write( "Divide both sides by $\"+-16+\"$
\n" ); document.write( " $\"+t%5E2+-+8t+-+9+=+0+\"$
\n" ); document.write( " $\"+%28+t+-+9+%29%2A%28+t+%2B+1+%29+=+0+\"$
\n" ); document.write( " $\"+t+=+9+\"$
\n" ); document.write( "The object hits the ground in 9 sec
\n" ); document.write( "The other solution is $\"+t+=+-1+\"$ sec
\n" ); document.write( "which is not possible.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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