The shed is filled with sawdust whose density (mass/unit volume) at any point is proportional to the distance of that point from the floor. The constant of proportionality is k. Calculate the total mass of sawdust in the shed. Your answer will have l, r, and k in it.
I really am having trouble finding the volume of a slice for this one, more specifically how I can relate l and r to the width, and then how would I set up the integral for this one? Any help appreciated.