🔍 Key Concepts

• Mechanical advantage of a tackle equals the number of supporting parts of line at the moving block, adjusted for where the hauling part is secured • When two tackles are used together (a compound tackle), the overall mechanical advantage is often the product of the individual advantages, depending on where the hauling part is attached • Compare the number of line parts in tackle #4 and tackle #10 in illustration D029DG and note which block is moving in each

💭 Think About

• First, for tackle #4 alone, how many parts of line are actually supporting the moving (lower) block and the weight? Is the hauling part counted or not in this case? • Then, for tackle #10 alone, how many parts of line support its moving block when you pull directly on its hauling part? What is the mechanical advantage of #10 by itself? • If the hauling part of tackle #10 is now bent to the weight hook of tackle #4, does that hook experience the full pull P or a multiplied force? How does that affect the total mechanical advantage on the final weight W?

✅ Before You Answer

• Be sure you are only counting line parts that directly support the moving block for each individual tackle • Confirm whether the hauling part of #10 is now acting on a moving block (the hook of #4) rather than a fixed point; this determines if the advantages multiply • After finding the combined mechanical advantage, check that your result matches one of the given choices A–D without rounding or assumptions