title: Unity 3D object with Rigidbody sliding
body: <p>I have a cube with <strong>Rigidbody</strong> attached to it would slide slightly whenever I pressed the play button. If I leave it for awhile, it would slide to other side of the screen. </p>
  
  <p>Anyone know how to solve this problem without using the "freeze position"? I don't know what I messed up in my project... </p>
  
  <p>This is what the object looks like: 
  <img src="https://i.stack.imgur.com/aisaB.png" alt="image"></p>
  
  <p>Note: I need to use the gravity.</p>
  
  <p>Thank you! </p>