For large raindrops, say with diameter 0.05 inches (or 0.004 feet), a size typical of drops in a thunderstorm), the force of air resistance is better modeled as a multiple of the square of the velocity. The differential equation now has the form
where a is another constant. In this case, the experimental evidence yields a value for a of 0.115. With the same initial condition, v(0) = 0, we have a new initial value problem. We will use Euler's Method to approximate the solution of this new problem, this time over the time interval from 0 to 2 seconds.