1. The problem statement, all variables and given/known data A boy launches a toy helicopter from the ground beside a building. It accelerates upward at 15 m/s^2. At the same time, another boy throws a rock down from the top of the building, which is 60 m above the ground. the helicopter and the rock collide at a height of 30 m. How fast was the rock thrown? Going of the problem: a=15 m/s^2 a=-8.8 m/s^2 x=30 m x=30 m xinitial= 60m xinital=60 m v? v=? 2. Relevant equations v^2=2aΔx 3. The attempt at a solution I tried averaging the numbers and used the above equation to get the average velocity. I got ≈12.5 m/s. However, I'm not sure if average velocity is exact enough for this problem. Does anyone have an alternate suggestion? Thanks!!