I would say the question really is, what is the difference between authority and force, rather than 'power'.

These types of questions are very much tied to the french enlightenment. Id suggest reading one of those 'short introduction' books on Rousseau. (french revolution thinker/philosopher)


Force ‘is a physical power’ and taken alone is nothing more. It is superior force that can give one group control over another. Force does not transform power into obedience or authority. Therefore, force requires constant application to be truly effective and furthermore, force has no claim to duty or obligation beyond the consequences of defying force.

(Quoted from various parts of an essay on 'force, rights and freedom' by me)
(It got a high grade by the way!, although not that Im claiming that this or any other answer is the only correct response.)