document.write( "Question 176111: The formula gives the height h in feet of an object after t seconds. Here is the initial velocity of the object expressed in feet per second. Suppose a toy rocket was launched from the ground straight up with an initial velocity of 64 ft/sec. How many seconds after launch was the rocket 48 feet above the ground? \n" ); document.write( "
Algebra.Com's Answer #131198 by stanbon(75887)\"\" \"About 
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The formula gives the height h in feet of an object after t seconds. Here is the initial velocity of the object expressed in feet per second. Suppose a toy rocket was launched from the ground straight up with an initial velocity of 64 ft/sec. How many seconds after launch was the rocket 48 feet above the ground?
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\n" ); document.write( "h(t) = -16t^2 + 64t
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\n" ); document.write( "-16t^2 + 64t = 48
\n" ); document.write( "-16t^2 + 64t - 48 = 0
\n" ); document.write( "Divide thru by -16 to get:
\n" ); document.write( "t^2 - 4t + 3 = 0
\n" ); document.write( "(t-3)(t-1) = 0
\n" ); document.write( "t = 1 sec or t = 3 seconds
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\n" ); document.write( "At 1 sec and at 3 seconds theobjectwas 48 ft above the ground.
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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