document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=193178>Question 193178</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An object that is projected straight downward with initial velocity of v feet per second is at a height from ground <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h=-16t%5E2-vt%2Bs+ ALIGN=MIDDLE  ALT=\"+h=-16t%5E2-vt%2Bs+\"   DISABLED_style= \"max-width:90%; height:auto;\" > , where s = initial height in feet, and t = time in seconds. If Bianca is standing on a ledge 46.75 feet above the ground and throws a penny straight down with an initial velocity of 12 feet per second, in how many seconds will it reach the ground? -- I tried as hard as I can to solve this word problem but the answer was not reasonable... please help me, thank you! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #145030 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=145030\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I think the key is that <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h ALIGN=MIDDLE  ALT=\"h\"   DISABLED_style= \"max-width:90%; height:auto;\" > is the height from the ground and the<BR>\n" );
document.write( "problem wants to know when the penny reaches ground, or when<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h+=+0 ALIGN=MIDDLE  ALT=\"h+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h+=+-16t%5E2+-+vt+%2B+s ALIGN=MIDDLE  ALT=\"h+=+-16t%5E2+-+vt+%2B+s\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0+=+-16t%5E2+-+vt+%2B+s ALIGN=MIDDLE  ALT=\"0+=+-16t%5E2+-+vt+%2B+s\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "given:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v+=+12 ALIGN=MIDDLE  ALT=\"v+=+12\"   DISABLED_style= \"max-width:90%; height:auto;\" > ft/sec<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s+=+46.75 ALIGN=MIDDLE  ALT=\"s+=+46.75\"   DISABLED_style= \"max-width:90%; height:auto;\" > ft<BR>\n" );
document.write( "Another key is that signs are already figured into the<BR>\n" );
document.write( "equation, so I don't have to worry about signs<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-16t%5E2+-+12t+%2B+46.75+=+0 ALIGN=MIDDLE  ALT=\"+-16t%5E2+-+12t+%2B+46.75+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Using the quadratic formula:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a+=+-16 ALIGN=MIDDLE  ALT=\"a+=+-16\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=b+=+-12 ALIGN=MIDDLE  ALT=\"b+=+-12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c+=+46.75 ALIGN=MIDDLE  ALT=\"c+=+46.75\"   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-%28-12%29+%2B-+sqrt%28+%28-12%29%5E2-4%2A%28-16%29%2A46.75+%29%29%2F%282%2A%28-16%29%29+ ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%2812+%2B-+sqrt%28+144+%2B+2992+%29%29%2F%28-32%29+ ALIGN=MIDDLE  ALT=\"t+=+%2812+%2B-+sqrt%28+144+%2B+2992+%29%29%2F%28-32%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%2812+%2B-+56%29%2F%28-32%29+ ALIGN=MIDDLE  ALT=\"t+=+%2812+%2B-+56%29%2F%28-32%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "If the numerator is (+), then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t ALIGN=MIDDLE  ALT=\"t\"   DISABLED_style= \"max-width:90%; height:auto;\" > is negative, and I can't have<BR>\n" );
document.write( "negative time, so the numerator must be negative<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-44%29%2F+%28-32%29 ALIGN=MIDDLE  ALT=\"t+=+%28-44%29%2F+%28-32%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+1.375 ALIGN=MIDDLE  ALT=\"t+=+1.375\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec<BR>\n" );
document.write( "The penny will reach the ground in 1.375 seconds<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-16t%5E2+-+12t+%2B+46.75+=+0 ALIGN=MIDDLE  ALT=\"+-16t%5E2+-+12t+%2B+46.75+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28-16%29%2A%281.375%29%5E2+-+12%2A1.375+%2B+46.75+=+0 ALIGN=MIDDLE  ALT=\"%28-16%29%2A%281.375%29%5E2+-+12%2A1.375+%2B+46.75+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "I don't have a calculator, but I think this checks out </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );