Relativity

Imagine you are an Actor walking with a xvelocity 5.
On and on a Ball is thrown in your direction at a xvelocity of -3 (ie Coming towards you when you walk Rightway)
Finally, as you walk, the View follows you with the same Velocity as the Actor (ie 5)
If you do a quite calculation, you'll easily find that there is a problem ! As you are walking at a Velocity of 5, with a View doing the same thing, and that the Ball is going the other way at a velocity of -3, you result with a Ball being Slowed Down (as it's now moving with a xvelocity of 2). And if you decide to walk Left (ie in thesame direction of the ball) the Ball then moves Faster (ie xvelocity becomes -8 ).
Am i making myself clear ?
What i would like to know is: can we make a velocity that is Relative to the View or Actor ? 
On and on a Ball is thrown in your direction at a xvelocity of -3 (ie Coming towards you when you walk Rightway)
Finally, as you walk, the View follows you with the same Velocity as the Actor (ie 5)
If you do a quite calculation, you'll easily find that there is a problem ! As you are walking at a Velocity of 5, with a View doing the same thing, and that the Ball is going the other way at a velocity of -3, you result with a Ball being Slowed Down (as it's now moving with a xvelocity of 2). And if you decide to walk Left (ie in thesame direction of the ball) the Ball then moves Faster (ie xvelocity becomes -8 ).
Am i making myself clear ?

