1.1. Water is leaking from a pipe. In a model, the rate of the leak, $L$ litres per second, is directly proportional to the square root of the speed of the water flow, $s$ m s^-1.

Given that the leak rate is 0.72 litres per second when the flow rate is 0.64 m s^-1,

find a complete equation for the model linking $L$ and $s$.

1.2. According to the model, find the speed of the water flow when the leak rate is 0.49 litres per second.

1.3. In an alternative model, the rate of the leak is given by the equation

$L=0.5s$

Find the non-zero speed of the water flow and the corresponding leak rate for which both models give the exact same values.