At the bottom of the water tower station, there is a circular water storage bucket with a radius of 5M and a height of 10M. There is a movable valve at the bottom of the bucket. When the water valve is opened, the water in the water storage bucket will be transported downwards along the water pipe connected with the water valve, with a radius of 0.2M Let the velocity of water entering the water pipe be v = 2GH(H is under the root sign (H is the height of water in the water storage bucket). Find out the water level at any moment and the time required to empty the water.