Look at the animation above. A projectile is shot into the air. Its path is determined by the horizontal and vertical components of motion. Notice how the resultant velocity vector is formed by the addition of the horizontal and vertical velocity vectors.
The vertical velocity decreases due to gravity while the horizontal velocity remains constant, assuming no air resistance. Notice at the top of the path the vertical velocity shrinks to zero so the resultant velocity of the projectile is the same as the horizontal velocity. Everywhere else along the projectile's path the resultant velocity vector is greater than either the horizontal or vertical velocity vectors.

Lets go straight into the exercises and combine vectors with projectile motion. Click on the exercises below.