i have calculated volume and weight from different size hailstones. i now have to calculate the wind speed needed to keep a hailstone of each size aloft. i am stuck on which equation to use... should i solve using D = 1/2(C*rho*A*v^2) ? for rho do i plug in the density of air or of each hailstone? i can only get as far as plugging in values for (drag coefficient) C=.5 and A for each respective hailstone. thanks!