Develop an expression for the quantity of liquid flowing over a sharp-edge V-notch of total angle 2θ, in terms of the head H above the bottom of the notch, the angle θ, and the coefficient of discharge Cd, assuming the velocity of approach to be small. If the rate of flow of water over a V-notch having θ = 35 deg is 42.5 dm3/s, find the head in centimeters.