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A worker throws his wrench downward from a height of 128 feet with an initial
\n" ); document.write( " velocity of 32 feet per second. The height of the wrench above the ground after
\n" ); document.write( " t seconds is given by S(t)= -16t^2-32t+128 .
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\n" ); document.write( "a. What is the height of the wrench after one second?
\n" ); document.write( "Substitute 1 for t in the given equation:
\n" ); document.write( "h = -16(1^1) - 32(1) + 128
\n" ); document.write( "h = -16 - 32 + 128
\n" ); document.write( "h = 80 ft after 1 sec
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\n" ); document.write( "b. How long does it take the wrench to reach the ground?
\n" ); document.write( "h = 0 when the wrench reaches the ground
\n" ); document.write( "-16t^2 - 32t + 128 = 0
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\n" ); document.write( "Simplify this, divide equation by -16, results:
\n" ); document.write( "+t^2 + 2t - 8 = 0
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\n" ); document.write( "Factor this to:
\n" ); document.write( "(t+4)(t-2) = 0
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\n" ); document.write( "The positive solution is what we want here.
\n" ); document.write( "t = 2 sec to reach the ground
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\n" ); document.write( "Check solution in original equation for t=2:
\n" ); document.write( "-16(2^2) - 32(2) + 128
\n" ); document.write( "-64 - 64 + 128 = 0
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