AddForce not moving object after instantiate

I’m trying to make a top down shooter and right now I’m getting the player to shoot. Basically I’m using the same line of code to move the projectile as I use to move the player, but it does not work.
This is the code:

 void FixedUpdate()
        this.GetComponent<Rigidbody2D>().AddForce(gameObject.transform.up * projectileSpeed);

This projectileSpeed is set to more than zero and I’ve tested it with a fixed float value, still nothing. It just gets instantiated and stands still. Any idea of what’s going on or what am I doing wrong? Thanks!

You are probably better off using .velocity which is how I normally handle bullets.

this.GetComponent<Rigidbody2D>().velocity = gameObject.transform.up * projectileSpeed;

This way you can set the velocity to a nice value like 100 and get a nice bullet effect
velocity does not need to be called in fixedupdate and can just be called once in start when the bullet is created.

Also if your working on a 2D game make sure transform.up is not making it move in the Z axis by checking the transform of the component while the game is running.