title: Box2d Revolute Joint vehicle with arm
body: <p>I am creating vehicle like this on the image:</p>
  
  <p><img src="https://i.stack.imgur.com/2quBV.png" alt="enter image description here"></p>
  
  <p>As you can see, there is:</p>
  
  <p>1) main vehicle body (Red rectangle) 
  2) wheels
  3) vehicles arm (black rectangle)</p>
  
  <p>Arm is connected with vehicles main body using Revolute joint in shown anchor center point, this arm can be moved up and down (with following angle limits) so as you can see it can move in 90 degrees only.</p>
  
  <p>My question is, I am moving this arm by applying angular impulse, it works, I can move arm, but it keeps falling down to the default position. I am struggling how to "disable" joint, so arm can be moved only using my controller so its not affected by gravity, so player can move arm slightly up for example and arm should stay in this position, instead of falling down.</p>
  
  <p>Any help would be great, thanks.</p>