Resetting momentum from respawned object?

Hi there, I'm using a basic script to respawn a ball falling with gravity, but one it collides with an object below it, after hitting the trigger below, it keeps the same momentum that it had while falling, and respawns travelling at the same speed and angle from the respawn point I set. I just based it off this video here: https://www.youtube.com/watch?v=nBgCeJBMT0k.

I want it to reset before it drops down again, with it falling very straight down, rather than with the momentum.

Here's my script, any help would be super!! I'm a very novice coder and new to Unity too, so if you could explain as easily as possible, that would be great!

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

public class Respawn : MonoBehaviour { public Rigidbody rb;

 [SerializeField]private Transform sphere;
 [SerializeField]private Transform respawnPoint;

 void Start() {
     rb = GetComponent<Rigidbody>();
 }


 void FixedUpdate() {
     if (Input.GetButtonDown ("up"))
         rb.isKinematic = true;
         rb.isKinematic = false;
 }

 // Use this for initialization
 void OnTriggerEnter (Collider other) {
     sphere.transform.position = respawnPoint.transform.position;
 }

}