title: Unity How to make GameObject Speed gain velocity
body: <p>I have a Torpedo in a Unity3D game that I'm making in Unity3D and I have a Torpedo fire out of a sub. How can I make the Torpedo fire like a Torpedo (start really slow) and then gain lots of momentum and speed up, like in movies.</p>
  
  <p>Below is my code for how I'm doing this, but it doesn't work very well.</p>
  
  <pre><code>    float torpedoSpeed = (0.00001f) * 155.2f;
  
     //move
      gameObject.transform.position += new Vector3(velocity, 0, 0) * 15.5f;
  </code></pre>