球的设置
football.addBodyCircle(football.getWidth()*0.5,football.getHeight()*0.5,football.getWidth()*0.5,1,5,.4,.3);
var force = 80;
var vec = new LGlobal.box2d.b2Vec2(-force*r*Math.cos(angle),-force*r*Math.sin(angle));
football.box2dBody.ApplyForce(vec, football.box2dBody.GetWorldCenter());