An arrow is a good example of a projectile. A projectile is an object upon which the only force acting is gravity. It usually undergoes vertical motion as well as horizontal motion. The projectile, or in this case the arrow, is always being accelerated downwards. (What is a Projectile,1996-2001) As long as an arrow is traveling forwards it has a constant horizontal vector. Its vertical vector changes as it goes up and down. The horizontal vector stays constant because the projectile is still traveling in one direction. The vertical vector changes because the projectile is moving in one direction, up, and then in another, down. It can also have a constant vertical vector though. If a projectile were pushed off a cliff with no rising motion, then it would also have a constant vertical vector. (Motion, Energy, and Simple Machines, 1996)

So what is a vector anyway? A vector is the direction of motion that a projectile travels. It is made up of a magnitude and a direction. (Vector, 1991) There are two vectors, a vertical vector and a horizontal vector. They are not related. Horizontal and vertical vectors do not affect one another. The vectors play a part in the trajectory of projectile flight.

Vectors are not the only factors that play a part in projectile flight and trajectory. There are also velocities. The two kinds of velocity are vertical and horizontal. A velocity is the speed a projectile is traveling in a certain direction. The velocities are completely separate of one another. (Velocity, 1991) For example the speed of which a projectile is traveling horizontally does not affect the speed of which it is traveling vertically. In the same sense, the vertical velocity will not affect how far a projectile...

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