document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=585199>Question 585199</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A ball is thrown downward from the top of a 90 story building. The distance, d inf feet, the ball is above the ground after t secconds is given by the function equation d=f(t) = -16t^2 -80t +800. After 2 seconds whaat is the distance of the ball from the ground? What is the height of the building, in feet? How long does it take for the ball to hit the ground?  \r<BR>\n" );
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document.write( "I do know that the distance from the ground is 576 feet. That is if it is correct. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #373218 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=373218\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A ball is thrown downward from the top of a 90 story building. The distance, d inf feet, the ball is above the ground after t seconds is given by the function equation d=f(t) = -16t^2 -80t +800. After 2 seconds whaat is the distance of the ball from the ground? What is the height of the building, in feet? How long does it take for the ball to hit the ground? <BR>\n" );
document.write( "I do know that the distance from the ground is 576 feet. That is if it is correct.<BR>\n" );
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document.write( "d=f(t) = -16t^2 -80t +800<BR>\n" );
document.write( "after 2 seconds, height of ball<BR>\n" );
document.write( "f(2)=-16(2^2)-80(2)+800<BR>\n" );
document.write( "=-64-160+800=576 feet<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Height of Bldg<BR>\n" );
document.write( "At 0 seconds the ball has dropped 0 feet from the top of the building.<BR>\n" );
document.write( "Height of building=f(0)=800 feet<BR>\n" );
document.write( "..<BR>\n" );
document.write( "When ball hits the ground, its distance above the ground=0<BR>\n" );
document.write( "0=-16t^2 -80t +800<BR>\n" );
document.write( "-16t^2 -80t +800=0<BR>\n" );
document.write( "t^2+5t-50=0<BR>\n" );
document.write( "(t+10)(t-5)=0<BR>\n" );
document.write( "t=-10 (reject, t>0)<BR>\n" );
document.write( "t=5 seconds<BR>\n" );
document.write( "ans:<BR>\n" );
document.write( "distance of the ball from the ground after 2 seconds=576 feet<BR>\n" );
document.write( "Height of building=800 feet<BR>\n" );
document.write( "How long it takes for the ball to hit the ground=5 seconds </SPAN>\n" );
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