I think physical force would althmore worsen the child attitude. He would be more stubborn and grow up hating parents. Indeed there is a fine line between using physical force and threatening. More threatening also would take the child to the same route and he would also practice the same traits on parents and other people. Children have the mindset to do whatever is told them not to do. So we need to tell them not do in a way that it is not a dictator 'NO'. Explain the cosequences of the action to the child.He would atleast start making an attempt to understand.