1. The problem statement, all variables and given/known data I have been given a question which I can't seem to get my head around fully for one reason. I keep finding myself stuck with 2 unknown variables. Here is the information given.. V (terminal velocity) = Unknown g (gravity acc.) = 9.81m/s2 d (diameter of particle) = ??? Pp = 1,100kg/m^3 Pm or "Pf" = 1,000kg/m^3 μ = 0.0012 Ns/m^2 I need to find the terminal velocity but this has been the only information specified about D's value in the question. "Vary D in a power law fashion, i.e.: Di = 2Di−1 i = 1,2, . . ,10 D0 = 0.01mm " 2. Relevant equations and 3. The attempt at a solution I have set up the equation using all the given information however I don't understand the instructions given in terms of the particle's diameter d's value. It is a programming assignment and I can't see myself progressing with it having 2 unknowns (As my code won't even function without a declared value for d). Is the above quote just telling me to use 0.01mm as my value for the diameter? I don't understand what varying "D in a power law fashion" is supposed to mean. I tried using the 2nd equation shown above to calculate the diameter by hand with the given information but I cannot do that either because I don't have the terminal velocity!! and that is what I am looking for to begin with. Just wondering if the reason I don't have a value for d is because of my understanding of the given quote or if I am lacking information to complete the question to begin with. If it happens to be a lack of information, am I by any chance overlooking something in the question? Because after I find the value of the terminal velocity I am supposed to find the Re (Reynold's Number) which implements both diameter and terminal velocity into the equation. Any help to the understanding of D's value given the information would be greatly appreciated by anyone. Understanding what is going on is always the hardest thing for me when it comes to programming, the coding usually serves little problem.