A U-tube filled with water is closed on one end. The tube is about one meter tall. When water is removed from the open end, the water level in the closed end does not change.

a. What is the pressure at point F before any water is removed?On the basis of your answer, is there a force exerted by the stopper on the top surface of the water?

b. The water level on the left is lowered until it reaches point A. Does the pressure at point A increase, decrease, or remain the same?Explain. On the basis of your answer, does the pressure at point D increase, decrease, or remain the same?Explain. If the pressure changes, how does the change in pressure at point A compare to the change in pressure at point D?Do the pressures at points E and F increase, decrease, or remain the same?How do the changes in pressure at these points compare to the change in pressure at point A?Does the forece exerted by the stopper on the top surface of the water increase, decrease, or remain the same?Explain.

c. Suppose that point F is 0.5 m above point E. Determin the pressure at point F. (Hint:What is the pressure at point E?) The density of water is p=1000kg/m^3, g=10m/s^2, and atmospheric pressure Po= 1.01 x 10^5 N/m^2.

d. Suppose instead that the tube is much taller than 1.0m. Calculate the distance above point E at which the pressure in the water would be zero (i.e, find the height of water above point E).

Original water level F E U 'D