A floating sonobuoy (sound-measuring device) is in equilibrium in the vertical position sh...

A floating sonobuoy (sound-measuring device) is in equilibrium in the vertical position shown. (Its center of mass is low enough that it is stable in this position.) The device is a 10-kg cylinder 1 m in length and 125 mm in diameter. The water density is 1025 kg/m3, and the buoyancy force supporting the buoy equals the weight of the water that would occupy the volume of the part of the cylinder below the surface. If you push the sonobuoy slightly deeper and release it, what is the frequency of the resulting vertical vibrations?