SOLUTION: If an object is given an initial velocity of v0 feet per second from a height of S0 feet, then its height S after t seconds is given by the formula S= -16t SQRD+vt+S . A rock is t

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Question 118874: If an object is given an initial velocity of v0 feet per second from a height of S0 feet, then its height S after t seconds is given by the formula S= -16t SQRD+vt+S . A rock is thrown into the air at 26 feet per second from a height of 13 feet. How long does it take to reach the earth?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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If an object is given an initial velocity of v0 feet per second from a height of S0 feet, then its height S after t seconds is given by the formula S= -16t SQRD+vt+S . A rock is thrown into the air at 26 feet per second from a height of 13 feet. How long does it take to reach the earth?
:
We can write it, the ground would be 0 ft;
:
-16t^2 + 26t + 13 = 0
:
Use the quadratic formula to solve this equation: a=-16; b=26; c=13
t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
:
t+=+%28-26+%2B-+sqrt%2826%5E2-4%2A-16%2A13+%29%29%2F%282%2A-16%29+
:
Do the math here.
you should get a positive solution of t = 2.026 sec to reach the ground
:
Check your solution in the original equation