document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=592133>Question 592133</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A golf ball is hit upward with a velocity of 66 feet per second (45 mph), its height h in feet above the ground after t seconds can be modeled by  .  <BR>\n" );
document.write( "a.	 Determine when the ball strikes the ground.\r<BR>\n" );
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document.write( "b.	 When is the height of the ball 50 feet?\r<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 #375853 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=375853\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A golf ball is hit upward with a velocity of 66 feet per second (45 mph), its height h in feet above the ground after t seconds can be modeled by <BR>\n" );
document.write( "h(t) = -16t^2+66t<BR>\n" );
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document.write( "a. Determine when the ball strikes the ground.<BR>\n" );
document.write( "The height will be zero when the ball trikes the ground:<BR>\n" );
document.write( "Solve:<BR>\n" );
document.write( "-16t^2+66t = 0<BR>\n" );
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document.write( "Factor:<BR>\n" );
document.write( "(-2t)(8t-33) = 0<BR>\n" );
document.write( "t = 0 before the ball is hit.<BR>\n" );
document.write( "t = 33/2 = 15.5 seconds (time it hits the ground)<BR>\n" );
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document.write( "b. When is the height of the ball 50 feet?<BR>\n" );
document.write( "Solve:<BR>\n" );
document.write( "-16t*2 + 66t = 50 feet<BR>\n" );
document.write( "-16t^2 + 66t - 50 = 0<BR>\n" );
document.write( "-2(8t^2 - 32t + 25) = 0<BR>\n" );
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document.write( "8t^2-32t+25 = 0<BR>\n" );
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document.write( "t = [32 +- sqrt(32^2-4*8*25)]/16<BR>\n" );
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document.write( "t = [32 +- sqrt(224)]/16<BR>\n" );
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document.write( "t = [32 +- sqrt(4*56)]/16<BR>\n" );
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document.write( "t = 1.021 sec. on the way up<BR>\n" );
document.write( "t = 1.065 sec. on the way down<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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