document.write( "Question 587211: use the height as a function of time in motion equation: h(t) = -16t squared + vt + c A baseball player hits a pitched ball when it is 4 ft above ground. The initial upward velocity is 80 ft/sec. How long will it take for the ball to hit the ground? \n" ); document.write( "
Algebra.Com's Answer #374032 by ankor@dixie-net.com(22740)\"\" \"About 
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use the height as a function of time in motion equation: h(t) = -16t squared + vt + c A baseball player hits a pitched ball when it is 4 ft above ground.
\n" ); document.write( "The initial upward velocity is 80 ft/sec. How long will it take for the ball to hit the ground?
\n" ); document.write( ":
\n" ); document.write( "h(t) = -16t^2 + vt + c
\n" ); document.write( "from the information given we know
\n" ); document.write( "v = 80
\n" ); document.write( "c = 4
\n" ); document.write( ":
\n" ); document.write( "h(t) = -16t^2 + 80t + 4
\n" ); document.write( "When the ball hits the ground we have h(t) = 0, therefore:
\n" ); document.write( "-16t^2 + 80t + 4 = 0
\n" ); document.write( "simplify divide by -4
\n" ); document.write( "4t^2 - 20t - 1 = 0
\n" ); document.write( "Use the quadratic formula to find t
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "x = t; b=-20, c=-1
\n" ); document.write( "\"t+=+%2820+%2B-+sqrt%28-20%5E2+-+4%2A4%2A-1+%29%29%2F%282%2A4%29+\"
\n" ); document.write( "Do the math, the positive solution
\n" ); document.write( "t = 5.0495 seconds
\n" ); document.write( ":
\n" ); document.write( "You should check this in the original problem\r
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