I'm having trouble with this problem here. A U-shaped tube with a horizontal portion of lenght L contains a liquid. What is the difference in height between the liquid columns in the vertical arms if the tube has an acceleration toward the right? There must be a net force to the left that presses the liquid to the left. In the right column there must be a pressure greater than the atmospheric pressure. But I don't know how to relate the lenght of the tube to the answer. Could someone please give me a clue how to solve this.