SOLUTION: This is from a test question which I struggled with. Use the projectile motion equation: h= -16t^2+V0t+h0 A baseball is hit from a rooftop 64 feet above the ground with an in

(A)  To answer (A), you need to substitute  h= 128 into the formula for the current height; 

     v0= 160 (initial upward velocity) and h0= 64 (initial height).


     Then you will get the equation


         -16t^2 + 160t + 64 = 128.      (A)


     I will left it to you to solve it on your own.



(B)  To anser (B), you need to solve the equation


                  -16t^2 + 160t + 64 = 0.    (B)


     In this case, the current height is 0 (zero), since the ball hits the ground (which is "level zero").



(C)  To answer this question, you need substitute t= 2 (2 seconds) into the given function


         h = -16*2^2 + 160*2 + 128.