ASVAB Mechanical Comprehension – Part 2
21. A rigid beam balanced in the center with effort applied opposite to the load represents which lever?
22. A lever in equilibrium has an effort of 40 ft·lb and a resistance of 8 ft·lb. What is the mechanical advantage?
23. An 80-lb child sits on one end of a seesaw. Another 80-lb child jumps down onto the other end from a platform. What is most likely to happen immediately after landing?
24. At minimum, how many pulleys are in a block and tackle system?
25. In a double-pulley system, how much force is needed to lift a 10 kg weight?
26. Which statement about a simple fixed pulley is false?
27. A 500-pound block is pulled up an incline 24 ft long that rises 6 ft. Neglect friction. How much force is needed to move the block up the incline?
28. If a wedge is made longer relative to its height, how does required force change for horizontal movement?
29. The well uses what simple machine to raise and lower a bucket?
30. In which direction does friction act on a skier going downhill?
31. Extending the reach of a crane will shift its:
32. Which shelf supports the most weight: one supported at both ends, one supported at center, or one supported at one end only?
33. What is tensile strength?
Quick Study Notes & Formula Reference
Study Tricks
Group similar topics together while you study: hydraulics and pressure questions, then gears and rotation, then levers and pulleys. This helps build patterns for the ASVAB mechanical comprehension section.
For gear problems, always write the teeth ratio and remember small gear speed = (big gear revolutions) × (big gear teeth ÷ small gear teeth).
For pulleys and inclined planes, convert the system to mechanical advantage first, then divide weight by MA to find required effort.
For lever problems, sketch fulcrum, load, and effort. Identify lever class by the relative positions: class I fulcrum between load and effort; class II load between fulcrum and effort; class III effort between fulcrum and load.
Essential Formulas to Memorize
Key Points and Exam Tips
Units matter. Convert consistently before plugging into formulas.
For speed/energy problems, mass often cancels when conserving energy, so numeric speed can be found without mass.
For rotation problems, note direction alternates with each meshing gear.
When a question mentions “double pulley” or “block and tackle,” check whether the system gives MA = 2 or more.
For hydraulics, remember pressure transmits equally; force is scaled by piston area while work is conserved (smaller force over larger distance).