StreetLight/Assets/Pong/Ball.cs

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

public class Ball : MonoBehaviour
{
    public bool IsInUse { get; private set; }
    public float speed = 5f;

    public void Recenter()
    {
        var component = GetComponent<Rigidbody>();
        component.velocity = Vector3.zero;
        component.transform.position = Vector3.zero;

        IsInUse = false;
    }

    public void Kickoff()
    {
        float sx = Random.Range(0, 2) == 0 ? -1 : 1;
        float sz = Random.Range(0, 2) == 0 ? -1 : 1;

        GetComponent<Rigidbody>().velocity = new Vector3(speed * sx, 0f, speed * sz);

        IsInUse = true;
    }
}