It is not correct saying that no force is applied. A photon carries momentum [see PE here][1] so on reflection there is momentum transfer. This is the idea behind laser propulsion discussed [here][2]. Concerning the speed it is even more complicated. The fact that light gets reflected usually requires an abrupt change in the index of refraction. To get reflected, hence, the photon interacts with the medium that reflects it. So it penetrates the medium to some extend. This takes [time][3] especially as the speed of light is slower in the medium, due to the interaction of the electric field with the surrounding matter. The speed of light in a dielectric medium is often subject of discussions as shown [here][4]. Unfortunately the accepted answer in that discussion is not really satisfying as the slowing down does not require loss of energy nor is it stochastic. It is better to look at the overall electromagnetic wave and its interaction with a surrounding that can give an electromagnetic response. In any case, thinking about light (particle, wave or what) and, furthermore, its interaction with matter is sort of mind boggling. [1]: http://physics.stackexchange.com/questions/2229/if-photons-have-no-mass-how-can-they-have-momentum [2]: http://space.stackexchange.com/questions/792/laser-propulsion-possible [3]: http://physics.stackexchange.com/questions/125906/expectation-value-for-the-time-of-a-photon-reflection [4]: http://physics.stackexchange.com/questions/53869/what-is-a-photons-speed-inside-a-dieletric