A U-tube is filled with water, and the two arms are capped.The tube is cylindrical, and the right arm has twice the radius of the left arm. The caps have negligible mass, are watertight, and can freely slide up and down the tube. If a 1.0-

kg-mass block is on the left cap, how much total mass must be placed on the right cap so that the caps equilibrate at equal height?

the area of the tubes determines how much mass (downward weight) can be applied. area is proportional to the square of radius, so a tube of twice the radius will have 4 times the area.

since the right tube is 4 times the area of the left, the water pressure which is the same for both sides will support 4 x 1.0 kg = 4.0 kg on the right cap ANS