Getting the Rigidbody of a Collider?

I have a Cube that is a Trigger. And a Sphere with a Rigidboy. I want the Sphere( that has a force applied (1.0f,0.0f,0.0f) ) to move in the Y plane when it enters the Cube.

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

public class GoingUp : MonoBehaviour
{
    private void OnTriggerEnter(Collider other)
    {
        Vector3 movement = new Vector3(0.0f, 5.0f, 0.0f);
        other.attachedRigidbody.AddForce(movement);
    }
}

But when it applies the vector movement the Sphere doesn’t move in the Y plane. What should I do?

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

 public class GoingUp : MonoBehaviour
 {
     private void OnTriggerEnter(Collider other)
     {
         Rigidbody _rb = other.attachedRigidbody; // Get the Rigidbody
         if (!_rb) // Check if there is a Rigidbody
              return; // Return if there is none

         Vector3 movement = new Vector3(0.0f, 5.0f, 0.0f);
         rb.velocity = Vector3.zero; // Resets all movements
         rb.AddForce(movement); // Apple movement
     }
 }