A D0= 10-m-diameter tank is initially filled with water 2 m above the center of a D = 10-c...

A D0= 10-m-diameter tank is initially filled with water 2 m above the center of a D = 10-cm-diameter valve near the bottom. The tank surface is open to the atmosphere, and the tank drains through a L= 100-m-long pipe connected to the valve. The friction factor of the pipe is given to be f=0.015, and the discharge velocity is expressed as

where z is the water height above the center of the valve. Determine (a) the initial discharge velocity from the tank and (b) the time required to empty the tank. The tank can be considered to be empty when the water level drops to the center of the valve.