Question

Cross-sectional area of both the limbs are equal. The difference in heights of the liquid in the two limbs when the system is given a constant velocity of $2\text{m/s}$ will be

• A. $10\text{cm}$
• B. $15\text{cm}$
• C. $18\text{cm}$
• D. Zero

Answer 1

The correct option is D Zero

System is moving with constant velocity of $2\text{m/s}$. In this case, acceleration $a=0$ for system in horizontal direction. Hence in the absence of acceleration, there will be no pseudo force applied on the fluid mass in its frame of reference. The net force on the fluid mass will be its weight (acting vertically downwards).

Hence, the free liquid surface will remain perfectly horizontal, as free surface of the liquid will be oriented $\perp$ to net force. So, liquid level in both the limbs will be the same as initial i.e no difference in heights.
Therefore, correct option is (d).