🔍 Key Concepts

• VCG (Vertical Center of Gravity) of a liquid added to a tank is usually taken at the centroid (mid-depth) of the added liquid layer, measured from the tank baseline or reference point • Relationship between existing depth in the tank and the final full depth when the tank is filled • How to express the vertical position of the added portion only, not the whole tank or existing liquid

💭 Think About

• First, sketch or imagine the tank depth and mark the bottom, current liquid level at 5.0 ft, and the final full level. Where is the middle of just the liquid that will be added? • Think of the added ballast as a separate layer: what is its thickness, and what is the midpoint of that layer measured from the tank bottom? • Compare your computed midpoint value with the answer choices and check which is closest to the vertical center of the added liquid portion.

✅ Before You Answer

• Be sure you are finding the VCG of the added liquid only, not the combined liquid in the tank after filling • Verify you are using the midpoint of the added layer’s depth (top + bottom ÷ 2) measured from the same vertical reference • Confirm that your final number is within the physical height of the tank and makes sense relative to the starting 5.0 ft level