A cylindrical tank with a diameter of 50 mm is drained by the force of gravity through an orifice at the bottom. The diameter of the orifice is 5 mm and the linear velocity through the orifice is given as = (2gh ). If the initial height of water in the tank is 0.4 m, find

a-)The expression for height as a function of time (15 points)

b-)The time it takes to drain the tank to 20 mm (10 points)