**PBL Projectile Motion Project: Launching a Clementine**

II. Questions (cont.)

II. Questions

II. Questions (cont.)

What is the significance of the vertex and the zeros of a quadratic equation in modeling projectile motion?

The vertex gives you your maximum height and your mid-point for the x axis. By using the equation (-b/2a) and plugging the resulting value into the original equation, you get the maximum height.

The zeros of the equation are the starting and ending

points of the object's path. They are the x intercepts.

They signify the moment the object leaves the ground, and the moment it hits again. The intercepts show how long the object was in the air.

Occupations That Use Projectile Motion

Occupation:

One occupation involves an NHL hockey player. The distance and velocity of a shot taken on net involves projectile motion. The time it takes for the player to take the shot can be inserted into the equation. Also, the distance between the player and the net allows for one to find the final velocity and intercepts.

I. Graph

What physical conditions might alter your equation?

It is hard to keep the force put on the object the same for each throw. Some throws were longer or shorter than others. Human error can alter the average time, or distance greatly. More specifically, reaction time when starting or stopping the stopwatch. If someone presses the stopwatch too early or does not stop at the exact time, the data can be incorrect.

**By: Julia Lawlor and Carson Hunt, P.3**

Why are quadratic equations used to model projectile motion instead of another type of function?

In projectile motion, you need to find the height, the time and the velocity. Quadratic equations are often modeled after the original equation:

For projectile motion, "t" (time) is used for x and the equation incorporates velocity. The equation is used because it most accurately represents what variables need to be found.

Occupations That Use Projectile Motion

Another occupation that uses projectile motion is a firefighter. Firefighters have to adjust the angle and distance of the hose in order to successfully extinguish a fire. A longer distance in a shorter time can be used in the equation, and the velocity of the speed of the water is also taken into account.

Occupations That Use Projectile Motion

Finally, another occupation that involves projectile motion is an astronaut. When they take off in a rocket, the rocket follows the projectile path created by the scientists. The time it takes for the rocket to launch and the distance it will travel are both used in the equations for figuring out projectile motion. The time and distance can be used to find the velocity.