SOLUTION: A baseball is hit into the air, and its height s in feet after t seconds is given by s(t) = −16t2 + 112t + 2. (a) What is the height of the baseball when it is hit? (b) Afte

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: A baseball is hit into the air, and its height s in feet after t seconds is given by s(t) = −16t2 + 112t + 2. (a) What is the height of the baseball when it is hit? (b) Afte      Log On

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Question 1140349: A baseball is hit into the air, and its height s in feet after t seconds is given by s(t) = −16t2 + 112t + 2.
(a) What is the height of the baseball when it is hit?
(b) After how many seconds does the baseball reach its maximum height?
(c) What is the maximum height of the baseball?
(d) When does the ball hit the ground for the first time?

Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.
(a)  it is  at t= 0:  s(0) = 2  feet.



(b)  find the maximum of the quadratic function.


     t = x = -b%2F%282a%29 = -112%2F%282%2A%28-16%29%29 = 112%2F32 = 3.5 seconds



(c)  s%5Bmax%5D = s(3.5) = -16%2A3.5%5E2+%2B+112%2A3.5+%2B+2 = 198 feet



(d)  s(t) = 0:   -16*t^2 + 112*t + 2 = 0


                  8t^2 - 56t - 1 = 0


                  t = %2856+%2B-+sqrt%2856%5E2+%2B+4%2A8%29%29%2F%282%2A8%29 = %2856+%2B-+56.285%29%2F16.


                  Only positive root works  t = %2856%2B56.285%29%2F16 = 7.02 seconds.

Solved. All question are answered.

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    - Problem on a toy rocket launched vertically up from a tall platform

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