document.write( "Question 190845: Initial speed (velocity) of Vo will travel a distance of (s) meters, where s=4.9t^2 + Vot and t is measured in seconds. Solve for t.
\n" ); document.write( "Use 4.9t^2 + Vot=s\r
\n" ); document.write( "\n" ); document.write( "Downward speed:
\n" ); document.write( "An object thrown downward from 200-m cliff travels 91.2m in 4 sec. What was the initial velocity of the object. \n" ); document.write( "
Algebra.Com's Answer #143318 by ankor@dixie-net.com(22740)\"\" \"About 
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Initial speed (velocity) of Vo will travel a distance of (s) meters,
\n" ); document.write( " where s=4.9t^2 + Vot and t is measured in seconds. Solve for t.
\n" ); document.write( "Use 4.9t^2 + Vot = s
\n" ); document.write( ":
\n" ); document.write( "4.9t^2 + Vot - s = 0
\n" ); document.write( ":
\n" ); document.write( "Treat it as a quadratic equation, use the quadratic formula:
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "In this equation: x = t ; a = 4.9, b = Vo, c = -s
\n" ); document.write( ":
\n" ); document.write( "\"t+=+%28-Vo+%2B-+sqrt%28Vo%5E2+-+4+%2A+4.9+%2A+%28-s%29+%29%29%2F%282%2A4.9%29+\"
\n" ); document.write( ":
\n" ); document.write( "\"t+=+%28-Vo+%2B-+sqrt%28Vo%5E2+-+%28-19.6s%29+%29%29%2F%289.8%29+\"
\n" ); document.write( ":
\n" ); document.write( "\"t+=+%28-Vo+%2B-+sqrt%28Vo%5E2+%2B+19.6s+%29%29%2F%289.8%29+\"
\n" ); document.write( ":
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\n" ); document.write( "Downward speed:
\n" ); document.write( "An object thrown downward from 200-m cliff travels 91.2m in 4 sec. What was the initial velocity of the object.
\n" ); document.write( ":
\n" ); document.write( "4.9t^2 + Vot = s
\n" ); document.write( "Substitute 4 for t and 91.2 for s
\n" ); document.write( "4.9(4^2) + 4Vo = 91.2
\n" ); document.write( "4.9(16) + 4Vo = 91.2
\n" ); document.write( "78.4 + 4Vo = 91.2
\n" ); document.write( "4Vo = 91.2 - 78.4
\n" ); document.write( "4Vo = 12.8
\n" ); document.write( "Vo = \"12.8%2F4\"
\n" ); document.write( "Vo = 3.2 m/sec
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\n" ); document.write( "Check solution using Vo = 3.2 & s = 91.2 m
\n" ); document.write( "\"t+=+%28-Vo+%2B-+sqrt%28Vo%5E2+%2B+19.6s+%29%29%2F%289.8%29+\"
\n" ); document.write( ";
\n" ); document.write( "\"t+=+%28-3.2+%2B-+sqrt%283.2%5E2+%2B+19.6%2A91.2+%29%29%2F%289.8%29+\"
\n" ); document.write( ":
\n" ); document.write( "\"t+=+%28-3.2+%2B-+sqrt%2810.24+%2B+1787.52+%29%29%2F%289.8%29+\"
\n" ); document.write( ":
\n" ); document.write( "\"t+=+%28-3.2+%2B-+sqrt%281797.76+%29%29%2F%289.8%29+\"
\n" ); document.write( ":
\n" ); document.write( "Positive solution
\n" ); document.write( "\"t+=+%28-3.2+%2B42.4%29%2F%289.8%29+\"
\n" ); document.write( "t = \"39.2%2F9.8\"
\n" ); document.write( "t = 4 sec as given above
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