Diagrams

Gravity

In the following image it is shown that gravity is always pointed towards the ground.

Projectile Path

The next image shows the projectile path when ignoring air resistance.

http://www.lightandmatter.com/html_books/lm/ch06/ch06.html

Example with Air Resistance

Here is an example of what a free body diagram would look like with a bullet that does not ignore air resistance.

http://colgatephys111.blogspot.com/2011/11/physics-of-bullet-drop-problem.html