title: Unity ball with constant speed
body: <p>I'm making 2D mobile game and I have a ball, but my ball doesn't have a constant moving speed. What I need to do?
  When I build game on my android device, ball have a various speed. In that case, my game is not playable.</p>
  
  <p>I hope that someone can help me. Thanks.</p>
  
  <p>This is on my start function:</p>
  
  <pre><code>void Start () {
      GetComponent&lt;Rigidbody2D&gt; ()
          .AddForce (new Vector2 (1f, 0.5f)* Time.deltaTime * force);
  }
  </code></pre>
  
  <p>Is it a good practice if I used in code " Application.LoadLevel ("__Scena_0"); " to load existing scene when I lose " life" ? Problem happens when I lost " life " and try playing game in second chance.</p>
  
  <p>My update function is about OnTriggerEnter2D when my ball hit trigger objects.</p>
  
  <p>EDIT 23.12.2015. : problem solve with adding physics material (fiction 0) and adding to script:</p>
  
  <pre><code>using UnityEngine.SceneManagement;
  ...
  SceneManager.LoadScene ("MainScene");
  </code></pre>