SOLUTION: A ball is thrown straight upward from the ground. Its height above the ground in meters after t seconds is given by -4.9t2 + 30t + c. Find the value for the constant c.

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Question 938259: A ball is thrown straight upward from the ground. Its height above the ground in meters after t seconds is given by -4.9t2 + 30t + c.

Find the value for the constant c.
Find the values of t that make the height zero and give a practical interpretation of each value.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+h%28t%29+=+-4.9t%5E2+%2B+30t+%2B+c+
To find +c+, set +t+=+0+
+h%280%29+=+0+ ( height above ground is zero at +t+=+0+ )
+0+=+-4.9%2A0%5E2+%2B+30%2A0+%2B+c+
+c+=+0+
--------------
+h%28t%29+=+0+
+-4.9t%5E2+%2B+30t+=+0+
+t%2A%28+-4.9t+%2B+30+%29+=+0+,
+t+=+0+
+4.9t+=+30+
+t+=+6.1224+ sec
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here's the plot:
+graph%28+400%2C+400%2C+-5%2C+7%2C+-5%2C+50%2C+-4.9x%5E2+%2B+30x+%29+