document.write( "Question 1192587: A stone is thrown vertically upward from a 20 foot platform at a rate of 160 ft per second. The height is the stone is modeled by the quadratic function f(x)=-16t^2+160t+20\r
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\n" ); document.write( "\n" ); document.write( "c)how long will it take for the taco to hit the ground? \n" ); document.write( "
Algebra.Com's Answer #824463 by ikleyn(52800)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "A stone is thrown vertically upward from a 20 foot platform at a rate of 160 ft per second.
\n" ); document.write( "The height \"highlight%28cross%28is%29%29\" of the stone is modeled by the quadratic function \"highlight%28cross%28f%28x%29%29%29\" f(t) = -16t^2 + 160t + 20.
\n" ); document.write( "a) how long will it take for the stone to reach its maximum height?
\n" ); document.write( "b) what is the maximum height of the stone?
\n" ); document.write( "c) how long will it take for the taco to hit the ground?
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document.write( "The function f(t) = -16t^2 + 160t + 20  is a quadratic function, whose plot is a parabola opened down.\r\n" );
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document.write( "This quadratic function has the maximum at the value of its argument  t = \"-b%2F%282a%29\", where \r\n" );
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document.write( "\"a\" is the coefficient at  t^2  and \"b\" is the coefficient at t.\r\n" );
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document.write( "In your case, a= -16,  b= 160, so the function gets the maximum at  t = \"-160%2F%282%2A%28-16%29%29\" = 5 seconds.\r\n" );
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document.write( "So, the ball gets the maximum height  5 seconds after is hit straight up. \r\n" );
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document.write( "It is the ANSWER to question (a).\r\n" );
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document.write( "The maximum height is then  f(5) = -16*5^2 + 120*5 + 20 = 220 feet.    \r\n" );
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document.write( "It is the ANSWER to question (b).\r\n" );
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document.write( "                      Regarding your question (c) . . . \r\n" );
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document.write( "    |       Question (c) asks about some tako, but I do not know        |\r\n" );
document.write( "    |    which tako do you mean and how does it relate to the problem.  |\r\n" );
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document.write( "          Do you just celebrate the International FOOLs' Day, \r\n" );
document.write( "                   which is scheduled on April 1 ?\r\n" );
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\n" ); document.write( "\n" ); document.write( " Solved.\r
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\n" ); document.write( "\n" ); document.write( "To see many other similar solved problems,  look into the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Problem on a projectile moving vertically up and down\r
\n" ); document.write( "\n" ); document.write( "    - Problem on an arrow shot vertically upward\r
\n" ); document.write( "\n" ); document.write( "    - Problem on a ball thrown vertically up from the top of a tower \r
\n" ); document.write( "\n" ); document.write( "    - Problem on a toy rocket launched vertically up from a tall platform\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
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\n" ); document.write( "\n" ); document.write( "On finding the maximum/minimum of a quadratic function,  learn from the lessons \r
\n" ); document.write( "\n" ); document.write( "    - HOW TO complete the square to find the minimum/maximum of a quadratic function\r
\n" ); document.write( "\n" ); document.write( "    - Briefly on finding the minimum/maximum of a quadratic function\r
\n" ); document.write( "\n" ); document.write( "    - HOW TO complete the square to find the vertex of a parabola\r
\n" ); document.write( "\n" ); document.write( "    - Briefly on finding the vertex of a parabola\r
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\n" ); document.write( "\n" ); document.write( "On the  International  FOOLs'  day of  April,  1   see this  Wikipedia article\r
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\n" ); document.write( "\n" ); document.write( "https://en.wikipedia.org/wiki/April_Fools%27_Day\r
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