10.65 Water flows from a tank through a
2.6-m
length of galvanized iron pipe 26 mm in diameter. At the end of the pipe is an angle valve that is wide open. The tank is 2 m in diameter. Calculate the time required for the level in the tank to change from 10 m to 2 m . Hint: Develop an equation for
d(h)/(d)t
where
h
is the level and
t
if time. Then solve this equation numerically.