A block of mass m is placed on a wedge The wedge can be accelerated in four manners marked as `(1),(2),(3)` and (4) as shown. If the normal reactions in situation `(1),(2),(3)` and (4) are `N_(1),N_(2),N_(3)` and `N_(4)` respectively and acceleration with which the block slides on the wedge in situation are `b_(1),b_(2),b_(3)` and `b_(4)` respectively then