More useful version of the AddPhysicalImpact script from the fBasic Asset.

FBasic_AddPhysicalImpact.cs

using UnityEngine;
using UnityEngine.Events;
using Random = UnityEngine.Random;

namespace FIMSpace.Basics
{
    /// <summary>
    /// Simple class which is adding physical impact on target rigidbody for provided time
    /// </summary>
    public class FBasic_AddPhysicalImpact : MonoBehaviour
    {
        [SerializeField] private Rigidbody _targetRigidbody;
        [SerializeField] private Vector3 _pushDirection = Vector3.forward;
        [SerializeField] private float _pushDirectionSeconds = 1f;
        [SerializeField] private Vector3 _randomDirMultiplier = Vector3.zero;
        [SerializeField] private float _powerMultiplier = 10f;
        [SerializeField] private UnityEvent OnPhysicalImpactDisable;

        private Vector3 _randomImpact = Vector3.zero;
        private float _timer;

        private void Reset()
        {
            _targetRigidbody = GetComponentInChildren<Rigidbody>();
        }

        private void OnEnable()
        {
            if (_targetRigidbody == null)
            {
                enabled = false;
                return;
            }

            if (_randomDirMultiplier.x != 0f) _randomImpact.x = Random.Range(0f, _randomDirMultiplier.x);
            if (_randomDirMultiplier.y != 0f) _randomImpact.y = Random.Range(0f, _randomDirMultiplier.y);
            if (_randomDirMultiplier.z != 0f) _randomImpact.z = Random.Range(0f, _randomDirMultiplier.z);

            _randomImpact.Normalize();
            var sum = _randomImpact.x + _randomImpact.y + _randomImpact.z;
            if (sum != 0f) _randomImpact /= sum;
        }

        private void OnDisable()
        {
            OnPhysicalImpactDisable?.Invoke();
        }

        private void Update()
        {
            _targetRigidbody.AddForce((_pushDirection + _randomImpact) * _powerMultiplier, ForceMode.Force);

            if (_timer > _pushDirectionSeconds)
            {
                enabled = false;
                _timer = 0f;
            }

            _timer += Time.deltaTime;
        }
    }
}