A rigging instructor is teaching trainees how to calculate mechanical advantage. Match each described frictionless pulley system to its Ideal Mechanical Advantage (IMA) and the effort force required to lift a load.
- System 1: A single fixed pulley where the effort rope is pulled downward.IMA = 1; Effort = 120 lbs
- System 2: A single movable pulley where the rope is anchored to a ceiling support and the free end is pulled upward.IMA = 2; Effort = 60 lbs
- System 3: A block and tackle with two fixed pulleys and one movable pulley; the rope anchors to the movable block.IMA = 3; Effort = 40 lbs
- System 4: A block and tackle with two fixed pulleys and two movable pulleys; the rope anchors to the fixed block.IMA = 4; Effort = 30 lbs
Cevap
System 1 matches IMA = 1 (120 lbs), System 2 matches IMA = 2 (60 lbs), System 3 matches IMA = 3 (40 lbs), and System 4 matches IMA = 4 (30 lbs).
Each system's mechanical advantage corresponds directly to the number of supporting rope strands. Dividing the 120 lb load by the respective IMA yields the correct effort force.
Adım Adım Çözüm
Anahtar Kavram
The Ideal Mechanical Advantage of a pulley system equals the number of rope strands that directly support the movable pulley block.