I need the slow motion effect for my game (actually, make everything slower). My game is using physics, so I don't know how to make physics objects slow down. Any idea please?

It all depends on type of game you are creating for example if you just want things to fall down slower you can simply lower the gravity and it will simulate objects falling at a slower pace. It all comes down to what type of game you are creating another example would be movieclips if the character is moving and you want to slow it down you can lower its frame speed and the images will play at a lower speed and if you want to lower his movement it depends if you are using linearImpulse or gravity or Force ect. If you can give more details then Ill gladly provide some help ;)