document.write( "Question 389141: An object is launched with initial velocity of 22.5 meters per second (m/s) from a 75-meter tall platform. The equation for the object's height h at time t seconds after launched is h(t)=-4.9t^2+22.5t+75, where h is in meters. How long will it take for the object to reach the ground? what is the maximum height reached by the object? \n" ); document.write( "
Algebra.Com's Answer #275686 by nerdybill(7384)\"\" \"About 
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An object is launched with initial velocity of 22.5 meters per second (m/s) from a 75-meter tall platform. The equation for the object's height h at time t seconds after launched is h(t)=-4.9t^2+22.5t+75, where h is in meters. How long will it take for the object to reach the ground?
\n" ); document.write( "set h(t) to zero and solve for t:
\n" ); document.write( "0=-4.9t^2+22.5t+75
\n" ); document.write( "applying the quadratic formula, we get:
\n" ); document.write( "t = {-2.24, 6.83}
\n" ); document.write( "toss out the negative answer leaves:
\n" ); document.write( "t = 6.83 seconds
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\n" ); document.write( "what is the maximum height reached by the object?
\n" ); document.write( ".
\n" ); document.write( "The vertex is the max height. It reaches this at:
\n" ); document.write( "t = -b/(2a)
\n" ); document.write( "t = -22.5/(2*(-4.9))
\n" ); document.write( "t = -22.5/(-9.8)
\n" ); document.write( "t = 2.30 seconds
\n" ); document.write( ".
\n" ); document.write( "h(2.30) = -4.9(2.30)^2+22.5(2.30)+75 = 100.83 meters (max height)
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