🔍 Key Concepts

• Vector components of a force – how a fixed load can be resolved into components along and across the boom • How the angle of the boom to the horizontal changes the size of the force component along the boom (thrust) • What happens to sin θ and cos θ as the angle θ increases or decreases from the horizontal

💭 Think About

• Draw a simple sketch of a boom at a few angles (near horizontal, 45°, and near vertical) with the same downward load at the hook. How would the component of that load along the boom change? • Think about which trigonometric function (sin or cos) is associated with the force along the boom if the boom is drawn as the reference line, and how that function changes as the boom is raised or lowered. • Compare the thrust when the boom is nearly horizontal versus nearly vertical: in which case would the boom itself feel the greatest end-to-end compression?

✅ Before You Answer

• Be clear that thrust on a cargo boom means the compressive force along the length of the boom, not the total load on the hook. • For each answer choice, mentally test the extreme cases: boom almost horizontal (small angle to horizontal) and boom almost vertical (large angle to horizontal). • Verify which statement correctly matches how the component of a fixed load along the boom changes as the angle to the horizontal changes.