document.write( "Question 1153146: During the construction of a high-rise building, a worker accidentally dropped his portable electric screwdriver from a height of 400 ft. After t sec, the screwdriver had fallen a distance of
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Algebra.Com's Answer #775300 by ikleyn(52794) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "(a)  To determine \"how long . . . \", solve the equation\r\n" );
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document.write( "         16*t^2 = 400.\r\n" );
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document.write( "     It is easy to do\r\n" );
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document.write( "         t^2 =  \r\n" );
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document.write( "         t^2 = 25\r\n" );
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document.write( "         t = sqrt(25) = 5 seconds.    ANSWER\r\n" );
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document.write( "(b)  The average velocity =  =  = 80 ft/s.      ANSWER\r\n" );
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document.write( "(c)  In Calculus,  velocity is first derivative of the distance over the time\r\n" );
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document.write( "         v =  =  = 2*16*5 = 160 ft/s.\r\n" );
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document.write( "     In Physics,  v = g*t, where g is the gravity acceleration g = 2*16 ft/s^2 = 32 ft/s^2,  t = 5 seconds, \r\n" );
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document.write( "     so  v = 32*5 = 160 ft/s,  giving the same ANSWER\r\n" );
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