jerky movement 2D


I’m struggling with a jerky movement, I’m trying to move a ball using “Mathf.Sin”

  void Update(){
  Vector3 v = startPos;
  v.x += Mathf.Sin (Time.time * speed);
  transform.position = v;

any help to make the movement really smooth?

Did you try SmoothStep?
Remember that Mathf.Sin works with radians, not degrees. I had troubles with that in the past.