init: function{
 var mass = 1;
var width = 1, height = 1;
this.playerBody = new cp.Body(mass , cp.momentForBox(mass, width, height));
this.space.addBody(this.playerBody);

this.schedule(this.move);
},
move: function(dt){
this.space.step(dt);
this.playerBody.getPos().x += 2 * dt;
this.playerBody.getPos().y += 2 * dt;
}