Ball Drop Problem: Solving the Dual Impact Challenge

[ArbazAlam]

This problem has really been bugging me. After several attempts, I don't even know where to start anymore.

A ball is thrown straight up from the edge of the roof of a building. A second ball is dropped from the roof 2.00 s later. Air resistance may be ignored.

(a) If the height of the building is 60 m, what must be the initial speed of the first ball if both are to hit the ground at the same time?

 

[danago]

Well the first thing i would do is calculate the time it takes for the dropped ball to hit the ground. That should be a fairly simple calculation.

Next, what equation do you know which relates the displacement of an accelerating body to the time it travels for?