I can't add force to a rigidbody with a NavMeshAgent also attached?

Hi, I'm working on a relatively simple game in which the player must fight enemies. Anyway, I've been trying to add grenades that the player can throw on a button press, instantiating a grenade prefab, which will explode after a few seconds. I also want the grenade to damage and push the enemies within its radius. The damage works fine, but AddExplosionForce(), which I am using to push them back, doesn't seem to have any affect on the enemies. I have previously added a print() statement, and the code is being called correctly, and i'm not getting any errors.
Does anyone know why the enemy rigidbodies are not affected when I add force to them?
Here is the code attached to the grenade that calls the function attached to the enemy:

  void FixedUpdate () 
         {
             Vector3 explosionPos = transform.position;
             explodeTimer += Time.deltaTime;
             if (explodeTimer >= timeToExplode) 
             {
                 explodeTimer = 0f;
     
                 audio.Play ();
                 explosionParticles.transform.position = transform.position;
                 explosionParticles.Play ();
     
                 Collider[] hitColliders = Physics.OverlapSphere(grenadeCollider.center, grenadeCollider.radius);
                 foreach (Collider c in hitColliders) 
                 {
                     string hitTag = c.gameObject.tag;
                     if (hitTag == "Enemy") 
                     {
                         EnemyHealth enemyHealth = c.GetComponent <EnemyHealth> ();
                         enemyHealth.TakeDamage (grenadeDamage, false, new Vector3 (0, 0, 0));
                         EnemyMovement enemyMovement = c.GetComponent<EnemyMovement> ();
                         enemyMovement.ExplodeMove(explosionPos);
                     }
                 }
                 Destroy (grenadeBody);
                 Destroy (gameObject, 2f);
             }
         }

and here is the function attached to the enemy:

  public void ExplodeMove(Vector3 pos)
         {
             nav.Stop (true);
             rb.isKinematic = false;
             rb.AddForce (new Vector3 (0, 5, 0), ForceMode.Impulse);
             rb.AddExplosionForce (100f, pos, 10,2f,ForceMode.Impulse);
         }

Thanks