Refer to the following information for the next nine questions.

A water-filled balloon is dropped from the top of a building that is 50 meters above the ground. One second later, a rock is thrown upwards from the ground at the base of the building with an initial velocity of +15 m/s.

To simplify your calculations, you may use g = 10m/s^{2} and the fact that there is no air resistance acting on the balloon as it falls through the air.