Rigidbody.velocity Not working on parent rigidbody with four child rigidbodies attached to it

As the question states, I am trying to move a rigidbody 2d (an empty gameobject) that is holding four 2d gameobjects with rigidbody attahed to them. I am trying the move the parent rigidbody object using the rb.velocity but it is not moving the gameobject however the position values in the inspector are changin. When I am trying to move the parent gameobject after removing the child gameobjects, it is working and the same is working for the child gameobjects too… What possibly could be the issue. In the unity documentation(Unity - Manual: Rigidbody component reference) it is clearly mentioned that a parent object will move alongwith the child gameobjects.

Start with this thought: There should be only 1 Rigidbody, and it will govern the child objects.

If you have reason to attach a Rigidbody TO a Rigidbody, you must do so through a joint (even a fixed joint).