Rigidbody2D motion in Unity

I was working a 2d game on unity, I wrote a script to manage obstacles and how to spawn them and move them during the game play which I’ve provided below

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;

public class obstacle_manager : MonoBehaviour
{
    List<GameObject> obstacles;
    
    List<Rigidbody2D> rbd;
    int childCount, x;
    System.Random random;
    float radius;
    int max_speed, min_speed, i;
    // Start is called before the first frame update
    void Start()
    {
        childCount = transform.childCount;
        i = childCount-1;
        radius = Mathf.Sqrt(20*20 + 10*10) * 0 + 1;
        x=0;
        max_speed = 5;
        min_speed = 1;
        random = new System.Random();
        if (obstacles == null)
        {
            obstacles = new List<GameObject>();
        }
        if (rbd == null)
        {
            rbd = new List<Rigidbody2D>();
        }
        // Loop through each child and add it to the list
        for (int i = 0; i < childCount; i++)
        {
            Transform child = transform.GetChild(i);
            obstacles.Add(child.gameObject);
            rbd.Add(child.gameObject.GetComponent<Rigidbody2D>());
        }

        foreach(GameObject obs in obstacles){
            obs.SetActive(false);
        }
    }

    // Update is called once per frame
    void Update()
    {
        x = random.Next(100);
        if (x < childCount){
            
            GameObject obs = obstacles[x];
                if(obs.activeSelf == false){
                float angle = random.Next(360) * Mathf.Deg2Rad;
                Vector3 posn = new Vector3(radius * Mathf.Cos(angle), radius * Mathf.Sin(angle), 0);
                obs.transform.position =  posn;

                //float speed = (random.Next(max_speed-min_speed) + min_speed)/10;
                Vector2 impulse = new Vector2(5f,0f);//new Vector3(-speed * Mathf.Cos(angle), -speed * Mathf.Sin(angle), 0);
                rbd[x].AddForce(impulse, ForceMode2D.Impulse);
                Debug.Log(rbd[x].velocity);
                obs.SetActive(true);
                }
        }
    }
}

But each time I ran it, the obstacle did became active, but it’s speed was 0, and the same was given out in the console during debugging, I don’t how to proceed

I also tried changing velocity of the rigidbody by accessing the velocity attribute and reassigning it, it wasn’t helpful either

>Solution :

According to the Unity docs (https://docs.unity3d.com/ScriptReference/Rigidbody.AddForce.html)
Force can only be applied to an active Rigidbody. If a GameObject is inactive, AddForce has no effect.

So if I were you I would move the obs.SetActive(true) before the rbd[x].AddForce so the Update method would look like this:

void Update()
    {
        x = random.Next(100);
        if (x < childCount){
            
            GameObject obs = obstacles[x];
                if(obs.activeSelf == false){
                float angle = random.Next(360) * Mathf.Deg2Rad;
                Vector3 posn = new Vector3(radius * Mathf.Cos(angle), radius * Mathf.Sin(angle), 0);
                obs.transform.position =  posn;

                obs.SetActive(true);
                Vector2 impulse = new Vector2(5f,0f);//new Vector3(-speed * Mathf.Cos(angle), -speed * Mathf.Sin(angle), 0);
                rbd[x].AddForce(impulse, ForceMode2D.Impulse);
                Debug.Log(rbd[x].velocity);
                
                }
        }
    }