document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=336792>Question 336792</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If an object is propelled upward from ground level with an intial velocity of 64 ft. per sec, its height h in feet t seconds later is:<BR>\n" );
document.write( "h=-16t^2 = 64t<BR>\n" );
document.write( "(a) After how many seconds is the height 48 ft?<BR>\n" );
document.write( "(b) The object reaches its maximum height 2 sec after it is propelled. What is this maximum height?<BR>\n" );
document.write( "(c) After how many seconds does the object hit the ground?\r<BR>\n" );
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document.write( "I have read all of the examples that they give me in my math book, but i still have a hard time trying to understand these problems. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #241414 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=241414\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If an object is propelled upward from ground level with an intial velocity of 64 ft. per sec, its height h in feet t seconds later is:<BR>\n" );
document.write( "h=-16t^2 + 64t<BR>\n" );
document.write( "(a) After how many seconds is the height 48 ft?<BR>\n" );
document.write( "Let h=48 and solve for \"t\":<BR>\n" );
document.write( "-16t^2+64t-48 = 0<BR>\n" );
document.write( "-16(t^2-4t+3) = 0<BR>\n" );
document.write( "(t-3)(t-1) = -<BR>\n" );
document.write( "t= 1 sec or t = 3 sec<BR>\n" );
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document.write( "Ans: time = 1 sec on the way up and time = 3 sec on the way down.<BR>\n" );
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document.write( "(b) The object reaches its maximum height 2 sec after it is propelled. What is this maximum height?<BR>\n" );
document.write( "f(x) = -16t^2+64t<BR>\n" );
document.write( "f(2) = -16(4)+64(2) = 64 ft.<BR>\n" );
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document.write( "(c) After how many seconds does the object hit the ground?<BR>\n" );
document.write( "Let h = 0 and solve for \"t\":<BR>\n" );
document.write( "-16t^2+64t = 0<BR>\n" );
document.write( "-16t(t-4) = 0<BR>\n" );
document.write( "t = 0 or t = 4 seconds<BR>\n" );
document.write( "t = 0 seconds refers to the time at which the object is launched.<BR>\n" );
document.write( "t = 4 seconds refers to the time at which the object is back on the ground. <BR>\n" );
document.write( "======================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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