Joint Question

Hi guys. I have a problem.
I wanna a box joint at the vehicle. That:

I joint box to vehicle. This OK.
NxOgre::FixedJoint* fj = mPhysicsScene->createFixedJoint((NxOgre::RigidBody*)convexBody,(NxOgre::RigidBody*)mVehicle->mActor);
But dont move convexbody
if(mKeyboard->isKeyDown(OIS::KC_N))
{
std::cout << "PRESSED" << std::endl;
convexBody->addForceAtLocalPos(NxOgre::Vec3(10,0,0),NxOgre::Vec3(0,0,0));
}
Someone help. Why did not move my box??? How can i solve?

Perhaps the force is too weak. Did you check with the Visual Debugger that your force actually gets applied and shows off there?