PROJECTILE MOTION GRAPH

Interpreting Projectile Motion Graph

Projectile motion follows the two dimensional kinematics. The trajectory of the projectile is always a parabola. It is not a linear graph.
In the figure below the projectile motion graph is shown.
V_x is showing the Horizontal Component of the velocity of the projectile.
V_y is showing the Vertical Component of the velocity of the projectile.  

 Horizontal Component of the Velocity (V_x)

The horizontal component of the velocity does not changes and the displacements covered by the horizontal components of the velocity are uniform. Horizontal velocity component is equal to the initial velocity component. Gravity force does not affect or does not make any change in the horizontal velocity component of the velocity.

Vertical Component of the Velocity (V_y): 
Vertical component of the velocity does not remain constant during the projectile motion. Gravity force acts on it and changes the vertical component of the velocity of the projectile. The displacements covered by the vertical component of the velocity are not uniform. 

1.During the projectile motion, both the magnitude and direction changes.

2.If the projectile is moving in the upward direction, the vertical component of the velocity is in the upward direction and decrease in its magnitude.
3.When the projectile moves in the downward direction, the direction of the vertical components of the velocity is in the downward direction and increase in the magnitude.