A cubical block is floating in a liquid with half of its volume immersed in the liquid. When the whole system accelerates upwards with acceleration of g3, the fraction of volume immersed in the liquid will be

Fraction of volume immersed in the liquid Vin = (ρσ)V i.e., it depends upon the densities of the block and liquid.So there will be no change in it if system moves upward or downward with constant velocity or some acceleration.