What would happen to the mercury in the column if a barometer is accelerated upwards? In static condition, acceleration is g. When the system moves upward with an acceleration a, effective acceleration = g + a. The air above the mercury in the trough will press it with higher force (i.e the normal reaction force at this interface increases), so the pressure at this interface will be higher than atm. P . To make the pressure at the base of the column equal to this increased pressure, mercury rises in the column. Am I not right in thinking that on being accelerated upward the mercury would rise in the column? Please do point out where I am amiss if I am wrong.