SOLUTION: the height h in feet of a ball t seconds after being tossed upwards is given by the function h(t)=80t-16t^2 A.after how many seconds will it hit on the ground? B.what is its maxi

(a)  To answer this question, you need to solve this equation

         80t - 16t^2 = 0,

     
     which is the same as

         t*(80 - 16t) = 0.


      It has one root t= 0 and the other root  t =  = 5 seconds,

      which is your ANSWER.



(b)  The height function is a quadratic function which has the zeroes at  t= 0  and  t= 5.


     It has the maximum at x = midpoint between the roots 0 and 5, i.e. 2.5 seconds.


     So, substitute this value t = 2.5 seconds into the given height function and get your ANSWER

          = 80*2.5 - 16*2.5^2 = 100 feet.