document.write( "Question 1167542: the height h in feet of a ball t seconds after being tossed upwards is given by the function h(t)=80t-16t^2
\n" ); document.write( "A.after how many seconds will it hit on the ground?
\n" ); document.write( "B.what is its maximum height? \n" ); document.write( "

Algebra.Com's Answer #792144 by ikleyn(52803) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "

\r\n" );
document.write( "\r\n" );
document.write( "(a)  To answer this question, you need to solve this equation\r\n" );
document.write( "\r\n" );
document.write( "         80t - 16t^2 = 0,\r\n" );
document.write( "\r\n" );
document.write( "     \r\n" );
document.write( "     which is the same as\r\n" );
document.write( "\r\n" );
document.write( "         t*(80 - 16t) = 0.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "      It has one root t= 0 and the other root  t =  = 5 seconds,\r\n" );
document.write( "\r\n" );
document.write( "      which is your ANSWER.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "(b)  The height function is a quadratic function which has the zeroes at  t= 0  and  t= 5.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "     It has the maximum at x = midpoint between the roots 0 and 5, i.e. 2.5 seconds.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "     So, substitute this value t = 2.5 seconds into the given height function and get your ANSWER\r\n" );
document.write( "\r\n" );
document.write( "          = 80*2.5 - 16*2.5^2 = 100 feet.\r\n" );
document.write( "

\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "--------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In this site, there is a bunch of lessons on a projectile thrown/shot/launched vertically up\r
\n" ); document.write( "\n" ); document.write( "    - Introductory lesson on a projectile thrown-shot-launched vertically up \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( "\n" ); document.write( "Consider these lessons as your textbook, handbook, tutorials and (free of charge) home teacher.
\n" ); document.write( "Read them attentively and learn how to solve this type of problems once and for all.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the topic \"Projectiles launched/thrown and moving vertically up and dawn\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );