flickering on applying Force

Questions & Answers
1

HI , below mentioned is script attached to a cube but when it moves upwards it flickers. How can I make it smooth?
Any help on this would be great.

using UnityEngine;
 using System.Collections;

public class charcter_upwardmotion : MonoBehaviour {
	 	    
	void Start () 
	{	
		Vector3 dir = Quaternion.AngleAxis(105, Vector3.forward) * Vector3.right;
		this.rigidbody.AddForce(dir*6.5f,ForceMode.VelocityChange);//6.5f
	}
   }
2

this.rigidbody.AddForce(dir*6.5f,ForceMode.VelocityChange);//6.5f

// multiply your force by Time.deltaTime


this.rigidbody.AddForce(dir*6.5f * Time.deltaTime,ForceMode.VelocityChange);//6.5f