Say there is a nice fresh coating of good packing snow on the ground. You feel the need to take advantage of it and nail someone (your sister, your mom, your dad, your grandma, etc) in the face with a snowball. You make the snowball and wind up to throw it. However before you let it fly, you have to take into account several physics factors. One, how far away is your target? At what angle should you launch it at? Depending on the distance, an angle of 45° would deliver the farthest distance. Secondly, do you have a moving target on your hands? If so, you would want to throw the snowball ahead of your target, but in the path they would cross. Because it takes time for the snowball to accelerate through the air, your target would have a chance to move, duck, dodge or whatever before it hits them. If you want to really surprise them, you would aim farthur and then they would never know what hit them. As you can see, it would be very intelligent to consider some minor physics details before you let it fly.