document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1075365>Question 1075365</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A child wanders slowly down a circular staircase from the top of a tower. With x,y,z in feet and the origin at the base of the tower, her position t minutes from the start is given by<BR>\n" );
document.write( "x=15cost,y=15sint,z=120&#8722;5t.<BR>\n" );
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document.write( "(a) How tall is the tower? <BR>\n" );
document.write( "height = \r<BR>\n" );
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document.write( " ft\r<BR>\n" );
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document.write( "(b) When does the child reach the bottom? <BR>\n" );
document.write( "time = \r<BR>\n" );
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document.write( " minutes\r<BR>\n" );
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document.write( "(c) What is her speed at time tt? <BR>\n" );
document.write( "speed = \r<BR>\n" );
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document.write( " ft/min\r<BR>\n" );
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document.write( "(d) What is her acceleration at time tt? <BR>\n" );
document.write( "acceleration = \r<BR>\n" );
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document.write( " ft/min2 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #690063 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=690063\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> (a)\r<BR>\n" );
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document.write( "Plug t = 0 into the z equation to get\r<BR>\n" );
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document.write( "z = 120 - 5*t<BR>\n" );
document.write( "z = 120 - 5*0<BR>\n" );
document.write( "z = 120 - 0<BR>\n" );
document.write( "z = 120\r<BR>\n" );
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document.write( "This means that when the time is t = 0 minutes, they are at z = 120. \r<BR>\n" );
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document.write( "The tower is 120 feet tall.\r<BR>\n" );
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document.write( "(b)\r<BR>\n" );
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document.write( "The child will reach the bottom when z = 0\r<BR>\n" );
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document.write( "Plug z = 0 into the z equation and solve for t\r<BR>\n" );
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document.write( "z = 120 - 5*t<BR>\n" );
document.write( "0 = 120 - 5*t<BR>\n" );
document.write( "0 + 5*t = 120 - 5*t + 5*t<BR>\n" );
document.write( "5*t = 120<BR>\n" );
document.write( "5*t/5 = 120/5<BR>\n" );
document.write( "t = 24\r<BR>\n" );
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document.write( "The child will reach the bottom at t = 24 minutes\r<BR>\n" );
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document.write( "(c)\r<BR>\n" );
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document.write( "Unfortunately I don't have enough information to answer this problem. You wrote \"tt\" but didn't write any values after that. Please update the problem. Thank you. \r<BR>\n" );
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document.write( "(d)\r<BR>\n" );
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document.write( "As in part (c), the same issue happens with this part as well. There isn't enough information. Please update.  </SPAN>\n" );
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