1. The problem statement, all variables and given/known data A ball is thrown at 72km/h speed from top of a building. Building is 125m tall. 2. Relevant equations Distance travelled before it hit the ground is as follows: s = Ut + 0.5 gt^2 3. The attempt at a solution Using quadratic equation: x = -b±b^2 - 4ac / 2a The question is for part one: Find the time for the ball to drop to fifth of the height of the building. Now I'm not sure if that means to 25m or 100m?! For 25m = 1 second For 100m = 3.3852 I got these from the quadratic equation. Do they seem right? Thanks!