even if drag force i.e air resistance is greater in magnitude as compared to other force ,there will be no motion in the direction of drag force, right?motion will be still in direction of that 'other force 'but as it is less than drag force there will be deceleration ,am i right?

Answer 1

That depends

If you are in an car:

If it is taking off from a stop light and accelerating forward then Thrust is greater than Drag

If it is cruising along at constant velocity then Thrust forward equals drag back

If you take your foot off the gas and coast then Thrust becomes LESS than drag and you slow down. Net force (Thrust - Drag) is back (negative) but motion is still forward.