document.write( "Question 180859: The height h, in feet, of a stone thrown with an upward speed of 40 ft/s is given by the formula h=40t-16t^2, where t is the time, in seconds, since the stone was thrown. How long does it take the stone to reach the highest point of its path of motion? \n" ); document.write( "
Algebra.Com's Answer #137142 by rapaljer(4671)\"\" \"About 
You can put this solution on YOUR website!
Rewrite this equation as \r
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\n" ); document.write( "\n" ); document.write( "h =-16t^2 + 40t \r
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\n" ); document.write( "\n" ); document.write( "It is well-known that the highest point on a parabolic graph y=ax^2 +bx +c occurs at the value of \"x+=+-b%2F%282a%29\".\r
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\n" ); document.write( "\n" ); document.write( "In this equation for h=-16t^2 + 40t, the maximum value of h occurs when
\n" ); document.write( "\"t=-b%2F%282a%29+\"
\n" ); document.write( "\"t=%28-40%29%2F%282%2A-16%29+\"
\n" ); document.write( "\"t=%28-40%29%2F%28-32%29\"
\n" ); document.write( "\"t=10%2F8=5%2F4\" seconds\r
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\n" ); document.write( "\n" ); document.write( "R^2
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