A ball is thrown up from the edge of the roof of a building. A second ball is dropped from the roof 1.00 seconds later (ignore air resistance). If the height of the building is 20 meters, what must be the initial speed of the first ball if both are to hit the ground at the same time?

Question

littlebird · Answer

I would just like to know what formulas I should use.

anonymous · Answer

http://physics.stackexchange.com/questions/76948/can-you-help-me-solve-a-difficult-kinematics-problem <---- this website should help, it gives the formulas for this queston