Problem:

The great quake has finally happened and you and a small group of friends have been traped in a building that is now surrounded by water filled with mutant sharks. The nearest land is about one football field (100 meters) away , but the mutant sharks have figured out that any boats that get into the water probably have people in them and so they won't allow any boats of food safely across. Your food supply is running low so you send out a distress signal over your trusty cellular phone.

A rescue party arrives on the other side of the shark-filled water and they have supplies. Included in their supplies is a very special catapult which is easily modified to shoot food. Their first attempt to shoot the food at you fails because they compute the range of their shots without taking into account air resistance. They say they can't waste food on subsequent shots unless you can tell them exactly how fast and at what angle to shoot the food. You tell them to wait a few minutes because you have a computer program that computes trajectories including air resistance and that you'll give them instructions on how to shoot the next food shipment.

What instructions do you end up giving your rescuers (remember, things like gravitational acceleration can not be adjusted in the real world)?