document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1158668>Question 1158668</A>: <I><SPAN STYLE=\"word-break: break-all;\">  *CAN YOU PLEASE EXPLAIN HOW YOU GOT THIS ANSWER FOR STUDYING PURPOSES*<BR>\n" );
document.write( "Problem: A ball is thrown vertically upward into the air.  If the ball started from a height of 101 feet off the ground, use the following formula to represent the projection of the ball\r<BR>\n" );
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document.write( "            H=-16t^2+38t+101\r<BR>\n" );
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document.write( "where H is the height of the ball after t seconds have passed. Based on this information, answer the following questions.<BR>\n" );
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document.write( "1)When does the ball reach its maximum height?<BR>\n" );
document.write( "Your answer must be expressed as a decimal rounded to 2 decimal places with correct units. Hint: The maximum occurs at the vertex of the parabola.<BR>\n" );
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document.write( "2)What is the maximum height of the ball?<BR>\n" );
document.write( "Your answer must be expressed as a decimal rounded to 2 decimal places with correct units.<BR>\n" );
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document.write( "3)When does the ball return to the ground? <BR>\n" );
document.write( "You must use the quadratic formula to solve this problem. Your answer must be expressed as a decimal rounded to 2 decimal places with correct units.<BR>\n" );
document.write( "Hint: The ball reaches the ground when the height equals zero.  <BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #781626 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=781626\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> H=-16t^2+38t+101 <BR>\n" );
document.write( "It helps to draw this.<BR>\n" );
document.write( "The value of t at the highest point is where t=-b/2a, and b is 38 and a=-16<BR>\n" );
document.write( "That will occur when t=-38/-32 seconds or 1.1875  or 1.19 seconds\r<BR>\n" );
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document.write( "Put that value of t bad into the equation<BR>\n" );
document.write( "-16(1.1875^2)+38(1.1875)+101=-22.5625+45.125+101=123.5625 or 123.56 feet\r<BR>\n" );
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document.write( "set the equation = to 0 and solve using the quadratic formula. I will rewrite with a positive coefficient of the first term: 16t^2-38t-101=0<BR>\n" );
document.write( "t=(1/32)(38+/- sqrt 1444+6464; sqrt term =88.93<BR>\n" );
document.write( "the positive root is t=(126.93/32)=3.97 seconds<BR>\n" );
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