A section of uniform pipe is bent into an upright U shape and partially filled with water, which can then oscillate back and forth in simple harmonic motion. The inner radius of the pipe is r = 0.011 m. The radius of curvature of the curved part of the U is R = 0.15 m. When the water is not oscillating, the depth of the water in the straight sections is d = 0.21 m.
Write an expression for the mass of water in the tube, in terms of the defined quantities and the density of water, rho. Use the approximation r«R.