Stokes Law

F = kv^xa^yh^z

[M][L][T]^-2 = [L]^x[T]^-x[L]^y[M]^z[L]^-z[T]^-z

(a) Equating powers of [M]; 1 = z

(b) Equating powers of [L]; 1 = x+y-z

(c) Equating powers of [T]; -2 = -x-z

Substituting (a) into (c) gives x = 1

Substituting for x and z into (b) gives y = 1

So F = kvah, and it turns out that k = 6 p