Projectile motion you say? Well ... Let me draw a force diagram for two objects moving at the same speed (after being thrown or something). The first object is a ping pong ball.

The key to projectile motion is the idea that the vertical motion and the horizontal motion are essentially independent of each other. You can try a very simple ... Here is a diagram that shows ...

Projectile motion problems can easily become algebra problems that focus on identifying the right number in a diagram and substituting it into the correct equation. We want them to see projectile ...