Mechanical Comprehension Review for Armed Services Vocational Aptitude Battery (ASVAB) Study Guide
This article will help you prepare for the Mechanical Comprehension subtest of the ASVAB. It presents the most commonly tested concepts: basic and compound mechanical machines and devices, mechanical motion, fluid dynamics, properties of materials, and structural support.
Every day, often without even thinking about it, you use mechanical devices. These could be simple machines such as levers and pulleys, or more complex compound machines such as linkages and gears. The ability to understand and use mechanical concepts is important both for many tasks required in the armed services and in everyday life.
The Mechanical Comprehension subtest of ASVAB may cover topics you are familiar with, as well as some that are new. Understanding the concepts in this chapter will benefit you both for the exam and in your career in the armed services. After an introduction to the Mechanical Comprehension subtest, this chapter summarizes definitions and the most commonly tested mechanical concepts. It also suggests how you can add to your knowledge of mechanical concepts and related scientific and mathematical knowledge. At the end of the chapter, you get an opportunity to review what you've learned by answering sample Mechanical Comprehension questions like those found on the ASVAB.
What Mechanical Comprehension Questions are Like
The Mechanical Comprehension subtest covers a wide range of topics. It consists of 25 multiple-choice questions, which you will have 19 minutes to answer. Most questions require previous knowledge of the topic, while some questions will themselves provide all of the information you need to figure out the answer.
Some questions require you to identify various mechanical machines or devices. Some of the mechanical devices that may appear on the exam—and are covered in this chapter—include gears, pulleys, levers, fasteners, springs, gauges, hinges, and linkages.
Other questions require knowledge of mechanical motion such as velocity, acceleration, direction, and friction for both solid bodies and fluids. These questions test concepts such as the motion and acceleration of automobiles or the buoyancy and pressure of fluids.
The Mechanical Comprehension subtest also covers the properties of materials and the concept of structural support. The material properties include weight, strength, density, thermal properties, and center of gravity. Structural support includes concepts such as weight distribution.
A typical mechanical comprehension question will look something like this:
- What is the main function of a pulley?
- to increase the strength of a construction crane
- to override the power of an electric motor
- to add energy to a system
- to change the direction of a pulling force
The correct answer is d, to change the direction of a pulling force. Pulleys are used to change not the strength of a force but its direction.
Review of Mechanical Comprehension Concepts
As aforementioned, some of the mechanical concepts most likely to appear on the ASVAB include basic and compound machines, mechanical motion, the behavior of fluids, the properties of materials, and structural support.