Quote:

I just want that the movement of object be smooth on 30fps as on 60fps


lol - if you just have half the frames the result only can be half that smooth.
Another thing could be a missing/misplaced time_step in your movement code.

Always take a deep look on your statistic panel (F11) to see where the time is spent.

PS:
Quote:

Man are you lost,or something?

Don't be that rude to your helping hands...