Suppose you drop a 1 kg squirrel out of a helicopter 500m above the ground (sorry squirrel). We want to model its descent taking into account both the forces of gravity and air resistance. The most popular model for air resistance is that it is proportional to the velocity squared. Assume that the acceleration due to gravity is a constant -9.8m/s2 If the constant of proportionality for our squirrel is k = 0.4 N/(m/s)2, how long does it take the squirrel to reach the ground?