F 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

Let's use the second kinematic equation:

Δy = vot + 1/2gt²

Δy = 0 (3.5) + 1/2 (-9.8) (3.5) ²

Δy = - 4.9 (3.5) ² = - 60.03 m

So the ball falls 60.03 m, meaning that's the height of the building. The negative sign just means I put the y = 0 mark at the top of the building.

Make sense?