A solid cylinder 1m in diameter and 0.8m high is if uniform relative density 0.85 calculate the periodic time of small oscillations when cylinder floats with its axis vertical in sitll water?

A submarine cruising well below the surface of the sea levels a wake in the form of a cylinder which is symmetrical about the longitudinal axis of the submarine through the water, which is 5 m s-1, and decreases in direct propotion to the radius to zero at a radius of 6 m. calculate the force acting on the submarine and the minimum power required to keep the submarine moving at this speed. density of water=1025kg m-3?