title: Stopping linear velocity on a box2d object
body: <p>I have just added a linear impulse function to move my object from left to right when the user moves their finger back and forward across the screen. The object is also falling by the worlds gravity.</p>
  
  <p>After the object reaches a boundary i want to stop the linear impulse. I understand that i should add linear dampening however that then stops the gravity for applying its force.</p>
  
  <p>Is there anyway i can stop the side to side impulse without effecting the gravity.</p>
  
  <p>Thanks</p>