its 100feet in height and 40 lb/ft3 is density
Do you want the weight of the silo? Or the contents. What is the diameter of the silo, and the thickness of the walls?
If you're given the thickness of the walls, as well as the outer (or inner) radius, you can calculate it. For example, if it had a 50ft diameter, and 1ft thick walls: 1) Calculate the volume of a cylinder with 25 ft radius, 100 feet high. 2) Calculate the volume of a cylinder with 24 ft radius, 100 feet high. 3) Subtract the answer from 2) from the answer from 1). This will leave the volume of the walls, and thus the volume of the silo that has weight. 4) Multiply the volume by your given density of 40 lb/ft^3. This will give you the weight of the silo.
