document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1111603>Question 1111603</A>: <I><SPAN STYLE=\"word-break: break-all;\"> an object is projected straight up with an initial velocity of k ft. /sec. The height of the object, h, at any time, t, is given by the function h(t)= -16t^2+ kt. if the object returns to the ground at t=8 sec., find the height (in feet) of the object at t=7 sec.Explain in words your steps to finding the value of k.\r<BR>\n" );
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document.write( "I tried to find k but i could finish because i didn't know what to do after u plug in the numbers and simplify also i got a crazy number when i didn't simplify    </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #726595 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=726595\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> an object is projected straight up with an initial velocity of k ft. /sec. The height of the object, h, at any time, t, is given by the function h(t)= -16t^2+ kt. if the object returns to the ground at t=8 sec., find the height (in feet) of the object at t=7 sec.Explain in words your steps to finding the value of k.\r<BR>\n" );
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document.write( "I tried to find k but i could finish because i didn't know what to do after u plug in the numbers and simplify also i got a crazy number when i didn't simplify<BR>\n" );
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document.write( "IDK what you mean by a \"crazy number.\"<BR>\n" );
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document.write( "h(t)= -16t^2+ kt<BR>\n" );
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document.write( "A total flight time of 8 sec --> 4 seconds ascending and 4 second descending.<BR>\n" );
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document.write( "--> max height at 4 seconds<BR>\n" );
document.write( "Falling for 4 seconds --> h(4) = 16*4^2 = 256 feet for max height.<BR>\n" );
document.write( "Max height is the vertex of the parabola.<BR>\n" );
document.write( "Vertex is at t = -b/2a = -k/-32 @ t=4<BR>\n" );
document.write( "4 = k/32<BR>\n" );
document.write( "k = 128 ft/sec --- the launch speed<BR>\n" );
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document.write( "find the height (in feet) of the object at t=7 sec.<BR>\n" );
document.write( "h(t) = -16t^2 + 128t<BR>\n" );
document.write( "h(7) = -16*49 + 128*7 = 896 - 784 = 112 feet<BR>\n" );
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document.write( "PS  h(7) = h(1) = -16 + 128 = 112 feet\r<BR>\n" );
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