document.write( "Question 168517: The heoght in feet, s, of a ball thrown straight up is given by the function
\n" ); document.write( " s(t)=-16t^2 + 56t+40, where t is the time in seconds. Find the maximum height reached by the ball. \n" ); document.write( "

Algebra.Com's Answer #124604 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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The height in feet, s, of a ball thrown straight up is given by the function
\n" ); document.write( "s(t)=-16t^2 + 56t+40, where t is the time in seconds. Find the maximum height reached by the ball.
\n" ); document.write( ":
\n" ); document.write( "This is a quadratic equation, max height will be at axis of symmetry
\n" ); document.write( "The formula for this is x = -b/(2a)
\n" ); document.write( ":
\n" ); document.write( "In this equation: x = t; a =-16; b = 56
\n" ); document.write( "t = $\"%28-56%29%2F%282%2A-16%29\"$ = t = $\"%28-56%29%2F%28-32%29\"$
\n" ); document.write( "t = +1.75 seconds at max height
\n" ); document.write( ":
\n" ); document.write( "Find the max height, substitute 1.75 for t in the original equation,
\n" ); document.write( "s(t) = -16(1.75^2) + 56(1.75) + 40
\n" ); document.write( "s(t) = -16(3/0625) + 98 + 40
\n" ); document.write( "s(t) = -49 + 98 + 40
\n" ); document.write( "s(t) = 89 ft is max height \n" ); document.write( "

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