document.write( "Question 1158667: Problem: A ball is thrown vertically upward into the air. If the ball started from a height of 101 feet off the ground, use the following formula to represent the projection of the ball\r
\n" ); document.write( "\n" ); document.write( " H=-16t^2+38t+101\r
\n" ); document.write( "\n" ); document.write( "where H is the height of the ball after t seconds have passed. Based on this information, answer the following questions.
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\n" ); document.write( "1)When does the ball reach its maximum height?
\n" ); document.write( "Your answer must be expressed as a decimal rounded to 2 decimal places with correct units. Hint: The maximum occurs at the vertex of the parabola.
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\n" ); document.write( "\n" ); document.write( "2)What is the maximum height of the ball?
\n" ); document.write( "Your answer must be expressed as a decimal rounded to 2 decimal places with correct units.
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\n" ); document.write( "\n" ); document.write( "3)When does the ball return to the ground?
\n" ); document.write( "You must use the quadratic formula to solve this problem. Your answer must be expressed as a decimal rounded to 2 decimal places with correct units.
\n" ); document.write( "Hint: The ball reaches the ground when the height equals zero.
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Algebra.Com's Answer #781627 by MathLover1(20849)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "\"H=-16t%5E2%2B38t%2B101\"\r
\n" ); document.write( "\n" ); document.write( "1) maximum\r
\n" ); document.write( "\n" ); document.write( "you have a parabola, upside down, and max is at vertex\r
\n" ); document.write( "\n" ); document.write( "so, write your equation in vertex form\r
\n" ); document.write( "\n" ); document.write( "\"H=%28-16t%5E2%2B38t%29%2B101\".......factor out \"-16\"\r
\n" ); document.write( "\n" ); document.write( "\"H=-16%28t%5E2-38t%2F16%29%2B101\"\r
\n" ); document.write( "\n" ); document.write( "\"H=-16%28t%5E2-19t%2F8%29%2B101\"\r
\n" ); document.write( "\n" ); document.write( "\"H=-16%28t%5E2-%2819%2F8%29%2Bb%5E2%29-%28-16%29b%5E2%2B101\".........\"b=%2819%2F8%29%2F2=19%2F16\"\r
\n" ); document.write( "\n" ); document.write( "\"H=-16%28t%5E2-19t%2F8%2B%2819%2F16%29%5E2%29%2B16%2819%2F16%29%5E2%2B101\"\r
\n" ); document.write( "\n" ); document.write( "\"H=-16%28t-19%2F16%29%5E2%2B361%2F16%2B101\"\r
\n" ); document.write( "\n" ); document.write( "\"H=-16%28t-19%2F16%29%5E2%2B1977%2F16\"\r
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\n" ); document.write( "\n" ); document.write( "=> vertex is at(\"+19%2F16\", \"1977%2F16\")=( \"1.19\", \"123.56\")\r
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\n" ); document.write( "\n" ); document.write( "so, the ball will reach max in \"t=1.19\" seconds\r
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\n" ); document.write( "\n" ); document.write( "2).
\n" ); document.write( "the max height of the ball is \"123.56ft\"\r
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\n" ); document.write( "\n" ); document.write( "3.\r
\n" ); document.write( "\n" ); document.write( "the ball will return to the ground when \"H=0\"\r
\n" ); document.write( "\n" ); document.write( "\"0=-16t%5E2%2B38t%2B101\"..........solve for \"t\" using quadratic formula\r
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\n" ); document.write( "\n" ); document.write( "\"t=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a\"\r
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\n" ); document.write( "\n" ); document.write( "since \"a=-16\",\"+b=38\", and \"c=101\" we have\r
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\n" ); document.write( "\n" ); document.write( "\"t=%28-38%2B-sqrt%2838%5E2-4%28-16%29%2A101%29%29%2F%282%28-16%29%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"t=%28-38%2B-sqrt%281444%2B6464%29%29%2F%28-32%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"t=%28-38%2B-sqrt%287908%29%29%2F%28-32%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"t=%28-38%2B-88.93%29%2F%28-32%29\"\r
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\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "\"t=%28-38%2B88.93%29%2F%28-32%29=-1.59\"\r
\n" ); document.write( "\n" ); document.write( "or\r
\n" ); document.write( "\n" ); document.write( "\"t=%28-38-88.93%29%2F%28-32%29=3.97\"\r
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\n" ); document.write( "\n" ); document.write( "disregard negative solution\r
\n" ); document.write( "\n" ); document.write( "so, the ball will return to the ground in \"3.97\" seconds\r
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