How to make an object fall-down from the top after moving from its position to the defined target?

I’m a beginner in learning unity and #C so my question may be very basic. I write the below simple code for my object to move toward from its first position to the target position. Now, I want to make this object fall down (into a container) when it meets the target position which is the end of a conveyor.
Many thanks in advance for our help.

public Rigidbody rb;
public Transform target;
public float speed;

void Start()
    {
   
}

void FixedUpdate()
{
    Vector3 a = transform.position;
    Vector3 b = target.position;
    transform.position = Vector3.MoveTowards(a, b, speed);
       
}
     
   
}

The easiest way to do this would be to put a box collider at the end of the conveyer and set it as a trigger, then use an ‘OnTriggerEnter’ function to set the rigidbody on the object to fall and trigger a flag to stop the ‘MoveTowards’ from happening.