# What is projectile motion? Part 1

WHAT IS PROJECTILE MOTION
contributed by: Emma C
Date last updated: 9/30/11

Projectile motion is a three-dimensional motion. Galileo believed if you throw a ball at an angle other than straight up or down, it has two motions. It has the horizontal motion and the vertical motion. The horizontal motion is when you first throw the ball and it flies through the air. The vertical motion is when it falls to the ground. If you throw it at an upward angle, the ball will not land as far away as if u threw it straight forward and it fell. If you throw the ball forward, it will fly through the air much, much further. Either way, it still has the horizontal and vertical motion. Instead of a one-dimensional motion, which would be simply a straight line, projectile motion is known as a three-dimensional motion. A projectile is also called a parabola. The trajectory is affected by gravity. Motion can be thought of as a single movement. So, that means that projectile motion is a three-dimensional parabola movement.

 figure 1: Projectile Motion

 figure 2: Projectile Motion trajectory angles

GLOSSARY
Parabola:a type of curve such as that made by an object that is thrown up in the air and falls to the ground in a different place; a projectile

Trajectory: a curve that is followed by a parabola

CITATIONS

Hecht, Eugene. Physics. Belmont, California: Brooks/Cole Publishing Company, 1994. Print.
"mechanics." Encyclopædia Britannica. Encyclopædia Britannica Online School Edition.Encyclopædia Britannica, Inc., 2011. Web. 12 Sept. 2011.
"parabola." Encyclopædia Britannica. Encyclopædia Britannica Online School Edition.Encyclopædia Britannica, Inc., 2011. Web. 12 Sept. 2011.

ThinkQuest. “The Physics of Projectile Motion.” ThinkQuest, Web. 15 Sept. 2011.
Wikipedia. “Projectile Motion.” Wikipedia, 27 Sept. 2011. Web. 16 Sept. 2011.