Physics.bounceThreshold

public static float bounceThreshold ;

Description

Two colliding objects with a relative velocity below this will not bounce (default 2). Must be positive.

This value is usually changed in Edit->Project Settings->Physics inspector instead of from scripts.

using UnityEngine;

public class Example : MonoBehaviour
{
    void Start()
    {
        Physics.bounceThreshold = 1;
    }
}