🔍 Key Concepts

• How to find the vertical center of gravity (KG) of a layer of liquid added between two soundings • The difference between the initial sounding and the final (full) level of the tank • For a uniform liquid, the CG of the added layer lies at the mid‑depth of that added layer

💭 Think About

• Ask yourself: is the question asking for the CG of the whole tank, or only of the added liquid between the initial level and full? • What is the thickness of the added layer of liquid, and where is the midpoint of that layer measured from the tank bottom? • If the sounding is measured up from the bottom, how do you express the CG position of the added layer using the starting sounding and the thickness of the layer?

✅ Before You Answer

• Confirm that you are using the depth of the added layer only (final level minus initial sounding), not the total tank depth, when finding its midpoint • Make sure all distances are measured from the same reference (usually the tank bottom) • Double‑check that your final CG position falls between the initial sounding level and the full‑tank level, since it’s only for the added liquid