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Projectile Motion fired HORIZONTALLY!
When a projectile is projected horizontally, the object has two components to its velocity: horizontal and vertical. We name these Vx and Vy. The initial velocities are Vox and Voy. While the Vx is constant throughout the entire flight of the object, Vy accelerates constantly due to gravity.
Gravity is always constant. Everything is affected by gravity, and all the same. Ignoring air resistance, if a projectile is fired directly horizontal, the object will hit the ground at the same time as if the object were just falling after being dropped from the same height. This is because the vertical velocities of both the objects are the same, and accelerating constantly due to force of gravity. The projectile that is fired horizonally will have a range (distance) while the object that is dropped will not, due to the horizontal component of the velocity, but they will both contact the ground at the same time and fall at the same rate.
There are many variables that can be found using simple equations. You can find the height of the projectile at a given time, the initial velocity, the components of the velocity, the instantaneous horizontal and vertical velocites at a given time, and the range. height= y, initial velocity= Vo, components= Vox and Voy, instantaneous velocity= Vx and Vy, and range= x. Most variables can be found using these equations: Vox=Vo cos theta; Voy=Vo sin theta; x=Voxt; y=voyt+1/2gt^2; Vx=Vox; Vy=Voy+gt. Gravity is always constant at 9.8m/s^2 if the object is falling and at -9.8m/s^2 if it is moving upward.
http://www.physicsclassroom.com/Class/vectors/u3l2b3.gif- top picture
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