Jane is riding in a hot air balloon that is rising vertically at a
constant speed of 3 m/s over a lake. She drops a rock from the balloon
when the distance from the rock to the water is 50 m. Use g=10
m/s², and let up be the positive direction. Assume the origin
is on the surface of the water, what is the initial position of the
rock?

1. 0
2. 50 m
3. -50 m
4. None of the above.