document.write( "Question 952389: A model rocket is launched with an initial velocity of 250 ft/s. The height, h, in feet, of the rocket t seconds after the launch is given by
\n" ); document.write( "h = −16t2 + 250t.
\n" ); document.write( " How many seconds after launch will the rocket be 870 ft above the ground? Round to the nearest hundredth of a second. \n" ); document.write( "

Algebra.Com's Answer #581617 by lwsshak3(11628) $\"\"$ $\"About$

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A model rocket is launched with an initial velocity of 250 ft/s. The height, h, in feet, of the rocket t seconds after the launch is given by
\n" ); document.write( "h = −16t2 + 250t.
\n" ); document.write( "How many seconds after launch will the rocket be 870 ft above the ground? Round to the nearest hundredth of a second.
\n" ); document.write( "***
\n" ); document.write( "-16t^2+250t-870=0
\n" ); document.write( "solve for t using quadratic formula:
\n" ); document.write( " $\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"$
\n" ); document.write( "a=-16, b=250, c=-870
\n" ); document.write( "ans: the rocket be 870 ft above the ground:
\n" ); document.write( "after 5.23 sec on the way up
\n" ); document.write( "after 10.39 sec on the way down
\n" ); document.write( " \n" ); document.write( "

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