title: How do I apply a force to a body in the direction it is traveling (Box2D)?
body: <p>I'm using AndEngine/Box2d to develop a game. I have a ball that bounces around the screen. I've successfully made it ignore gravity by applying an opposite force, but it has a tenancy to slow down after the initial impulse, even with the elasticity set to 1. Essentially I want to:</p>
  
  <p>if(speed &lt; <em>a number</em>)
  apply force or impulse (which is better?) in direction of motion</p>
  
  <p>How might I do this?</p>