AddForce not working on Instantiated Object

I had an object that was in my hierarchy and when certain conditions were met, a force (AddForce) was applied. This worked very well until I made a prefab out of the original object… now, the object is instantiated and it just drops till it hits the floor and the AddForce does nothing. I searched and it appears that applying a force to an object that has been instantiated has been problematic yet nothing I have read or tried over the past six hours seems to make any difference.

The object I am attempting to AddForce to is ‘tire_wheel_prefab_2’. Again, before this became a prefab and was instantiated, it worked perfectly. On the ‘tire_wheel_prefab_2 there is a Rigidbody added, ‘Use Gravity’ is checked, and ‘Is Kinematic’ is unchecked. The settings are identical to the object I used before (when it worked) but AddForce is doing nothing. The ‘sphere’ and ‘heart_2’ commands immediately above the AddForce do exactly what they are supposed to so I know that the conditions are being met.

Can someone assist me in getting the AddForce to work properly?

Sincerely,

Daryl G

 using Phidgets;
 using Phidgets.Events;
 using UnityEngine;
 using System.Collections;
 
 public class PhidgetsController : MonoBehaviour
 {
     private InterfaceKit InterfaceKitController = new InterfaceKit();
     private int arbitraryCounter = 0;
     private int oldarbitraryCounter = 0;
     public new ParticleSystem particleSystem;
 
     public GameObject sphere;
     public GameObject heart_2;
     public Rigidbody tire_wheel_prefab_2;
     public GameObject TextHintGUI;
     TextHints bPScript;
     public bool playsound = false;
 
     void Start()
     {
         particleSystem.Stop();
         Instantiate (tire_wheel_prefab_2, new Vector3(5.6f, 6f, 6f), Quaternion.Euler(270, 0, 0));
     }
     
     //Sensor Change event handler...Display sensor index and new value to the console
     void InterfaceKit_SensorChange(object sender,SensorChangeEventArgs e)
     {
         arbitraryCounter = e.Value;
     }
     
     void FixedUpdate()
     {
         if (arbitraryCounter>oldarbitraryCounter) {
             particleSystem.Play();
             if (playsound==false) {
                 audio.Play();
                 playsound=true;
             }
 
             bPScript = TextHintGUI.GetComponent <TextHints>();
         //if high bp is NOT selected (i.e., normal bp)
         if (bPScript.whichBPOption == false) {
             sphere.transform.localScale += new Vector3(((arbitraryCounter-500)/50) * Time.deltaTime, ((arbitraryCounter-500)/50) * Time.deltaTime, ((arbitraryCounter-500)/50) * Time.deltaTime);
             heart_2.transform.Rotate(Vector3.right, 20 * Time.deltaTime); //this rotates heart when pumping
             tire_wheel_prefab_2.AddForce(-30,5,10);