1. The problem statement, all variables and given/known data A rock is thrown vertically upward with a speed of 17.0 from the roof of a building that is 60.0 above the ground. Assume free fall. In how many seconds after being thrown does the rock strike the ground? 2. Relevant equations I used v^2 = vinitial^2 + 2a(y - yinitial) to find the speed when it hits the ground. I am trying to find the time and can't seem to locate a good equation to use.