That means that the best way to launch a high-altitude projectile is to send it flying at a 90-degree angle to the ground—straight up.

They are varying the initial angles and velocities to hit a target distance. Take advantage of student interest with the following strategies to help you integrate Angry Birds into your instruction.

Here's how I explained the concept of "angle of descent" back in 2006. But here's the bit that justifies Dawson's explanation of projectile motion.