SWDensity = 1025;
G = 9.8;

a = SWDensity * G;

Cd = 1.5;
diameter = 0.2032;
Area = (pi/4) * diameter^2;
Clinearize = (1.51*10^-3) / (7.78 * 10^-3)

b = 0.5 * SWDensity * Cd * Area * Clinearize;

mass = 38;

H = tf([a],[mass b 0]);

bode(H)