document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=140056>Question 140056</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A ball is thrown vertically upwards from the balcony of an apartment building.  The ball falls to the ground.  The height of the ball , h metres, above the ground after t seconds is given by h=-5t^2 +15t +45.\r<BR>\n" );
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document.write( "What is the height of the balcony? 45m?<BR>\n" );
document.write( "What is the maximum height reached by the ball?<BR>\n" );
document.write( "When will the ballreach a height of 55m?<BR>\n" );
document.write( "When will the ball hit the ground? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #102073 by </B><A HREF=/tutors/aboutme.mpl?userid=rapaljer><B>rapaljer(4671)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rapaljer><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/cgi-bin/show-face.mpl?user=rapaljer><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=102073\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> h=-5t^2 +15t +45\r<BR>\n" );
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document.write( "Yes, the height of the building is the height at t=0, which is 45 ft.\r<BR>\n" );
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document.write( "Maximum height of the parabola <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=ax%5E2+%2Bbx+%2Bc ALIGN=MIDDLE  ALT=\"y=ax%5E2+%2Bbx+%2Bc\"   DISABLED_style= \"max-width:90%; height:auto;\" > occurs at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=-b%2F%282a%29 ALIGN=MIDDLE  ALT=\"x=-b%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Maximum height at =<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=-15%2F%282%2A-5%29=15%2F10=3%2F2 ALIGN=MIDDLE  ALT=\"t=-15%2F%282%2A-5%29=15%2F10=3%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" > seconds.<BR>\n" );
document.write( "Maximum height = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-5%2A%283%2F2%29%5E2%2B15%2A%283%2F2%29%2B45 ALIGN=MIDDLE  ALT=\"-5%2A%283%2F2%29%5E2%2B15%2A%283%2F2%29%2B45\"   DISABLED_style= \"max-width:90%; height:auto;\" > feet<BR>\n" );
document.write( "Maximum height = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-5%289%2F4%29%2B45%2F2%2B45=-45%2F4%2B45%2F2%2B45 ALIGN=MIDDLE  ALT=\"-5%289%2F4%29%2B45%2F2%2B45=-45%2F4%2B45%2F2%2B45\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Maximum height = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-45%2F4%2B90%2F4%2B45=45%2F4%2B45=11.25%2B45+=56.25 ALIGN=MIDDLE  ALT=\"-45%2F4%2B90%2F4%2B45=45%2F4%2B45=11.25%2B45+=56.25\"   DISABLED_style= \"max-width:90%; height:auto;\" > feet\r<BR>\n" );
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document.write( "The ball reaches 55 feet when <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=55=-5t%5E2+%2B15t+%2B45 ALIGN=MIDDLE  ALT=\"55=-5t%5E2+%2B15t+%2B45\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0=-5t%5E2%2B15t-10 ALIGN=MIDDLE  ALT=\"0=-5t%5E2%2B15t-10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0=-5%28t%5E2-3t%2B2%29+ ALIGN=MIDDLE  ALT=\"0=-5%28t%5E2-3t%2B2%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0=-5%28t-1%29%28t-2%29+ ALIGN=MIDDLE  ALT=\"0=-5%28t-1%29%28t-2%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "t=1 and t=2 seconds (at t=1 sec going up, at t=2 seconds coming down!)\r<BR>\n" );
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document.write( "The ball hits the ground when h=0.\r<BR>\n" );
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document.write( "h=-5t^2 +15t +45<BR>\n" );
document.write( "0=-5t^2 +15t +45<BR>\n" );
document.write( "0=-5(t^2-3t-9)<BR>\n" );
document.write( "Solve this by quadratic formula, since it does not factor.  The answer will contain a radical.\r<BR>\n" );
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document.write( "R^2 \r<BR>\n" );
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document.write( " </SPAN>\n" );
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