If a ball dropped from a tower reaches the ground after 3.5 seconds, what is the height of the tower? given: g = -9.8 meters/second2 me i need thie correct answer

If you know the formula, the solution is easy.

  Distance = (1/2) · (acceleration) · (time)²

               =  (1/2)  ·  (9.8 m/s²)  ·  (3.5 sec)²

               =  (1/2)  ·  (9.8 m/s²)  ·  (12.25 s²)

               =        60.025 meters .


If you don't know the formula, you can still answer the question
without too much trouble. 
But I have to warn you:   It will involve thinking. 

Acceleration of gravity = 9.8 m/s² .

After falling for 3.5 seconds, the speed of the ball is (3.5 x 9.8) = 34.3 m/s .

The AVERAGE speed of the ball for the entire fall is

                            (1/2) (0 + 34.3)  =  17.15 m/s .

Traveling for 3.5 seconds at an average speed of  17.15 m/s ,
the ball covers a distance of

                        (3.5 sec) x (17.15 m/s)  =  60.025 m .