document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=87894>Question 87894</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Could someone help me please? The problem is:<BR>\n" );
document.write( "A ball is thrown upward from the roof of a building 100m tall with an initial velocity of 20m/s. When will the ball reach a height of 80m? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #63759 by </B><A HREF=/tutors/aboutme.mpl?userid=Earlsdon><B>Earlsdon(6294)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Earlsdon><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=63759\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Well, you can start with the function that gives the height, as a function of time, h(t) of an object propelled upward with an initial upward velocity of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v%5B0%5D%5D%5D ALIGN=MIDDLE  ALT=\"v%5B0%5D%5D%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >m/s from an initial height of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5B0%5D ALIGN=MIDDLE  ALT=\"h%5B0%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >m.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%28t%29+=+-4.9t%5E2%2Bv%5B0%5Dt%2Bh%5B0%5D ALIGN=MIDDLE  ALT=\"h%28t%29+=+-4.9t%5E2%2Bv%5B0%5Dt%2Bh%5B0%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "In this problem:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5B0%5D+=+100 ALIGN=MIDDLE  ALT=\"h%5B0%5D+=+100\"   DISABLED_style= \"max-width:90%; height:auto;\" >m.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v%5B0%5D+=+20 ALIGN=MIDDLE  ALT=\"v%5B0%5D+=+20\"   DISABLED_style= \"max-width:90%; height:auto;\" >m/s.<BR>\n" );
document.write( "You would like to know at what time, t, will h = 80 meters.<BR>\n" );
document.write( "Making the appropriate substitutions into the formula:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=80+=+-4.9t%5E2%2B20t%2B100 ALIGN=MIDDLE  ALT=\"80+=+-4.9t%5E2%2B20t%2B100\"   DISABLED_style= \"max-width:90%; height:auto;\" > Subtract 80 from both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-4.9t%5E2%2B20t%2B20+=+0 ALIGN=MIDDLE  ALT=\"-4.9t%5E2%2B20t%2B20+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > Solve this quadratic equation using the quadratic formula: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a ALIGN=MIDDLE  ALT=\"t+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a\"   DISABLED_style= \"max-width:90%; height:auto;\" > In this equation, a = -4.9, b = 20, and c = 20<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-20%2B-sqrt%2820%5E2-4%28-4.9%29%2820%29%29%29%2F2%28-4.9%29 ALIGN=MIDDLE  ALT=\"t+=+%28-20%2B-sqrt%2820%5E2-4%28-4.9%29%2820%29%29%29%2F2%28-4.9%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplifying this, you'll get:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-20%2B-sqrt%28400-%28-392%29%29%29%2F-9.8 ALIGN=MIDDLE  ALT=\"t+=+%28-20%2B-sqrt%28400-%28-392%29%29%29%2F-9.8\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-20%2B-sqrt%28792%29%29%2F-9.8 ALIGN=MIDDLE  ALT=\"t+=+%28-20%2B-sqrt%28792%29%29%2F-9.8\"   DISABLED_style= \"max-width:90%; height:auto;\" > Evaluating this gets you:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+4.912499 ALIGN=MIDDLE  ALT=\"t+=+4.912499\"   DISABLED_style= \"max-width:90%; height:auto;\" > or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+-0.830866 ALIGN=MIDDLE  ALT=\"t+=+-0.830866\"   DISABLED_style= \"max-width:90%; height:auto;\" > Discard the negative solution.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+4.9 ALIGN=MIDDLE  ALT=\"t+=+4.9\"   DISABLED_style= \"max-width:90%; height:auto;\" >seconds. </SPAN>\n" );
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