Free ASVAB Practice Tests | ASVAB Test Bank

Mechanical Comprehension

Sam can do 50 ft. lb. of work in 2 minutes and 5 seconds. What would Sam have to do to increase his power output?

do the work in 2 minutes

Power is the rate of doing work or \(\frac{W}{t}\). To increase power, increase the work being done in the same amount of time or do the same amount of work in less time.

Automotive Information

Too much fuel results in a __________ air-fuel mixture that burns quicker and cooler.

rich

The stoichiometric ratio defines the proper ratio of air to fuel necessary so that an engine burns all fuel with no excess air. For gasoline fuel, the stoichiometric ratio is about 14.7:1 or for every one gram of fuel, 14.7 grams of air are required. Too much air results in a lean air-fuel mixture that burns more slowly and hotter while too much fuel results in a rich mixture that burns quicker and cooler.

Word Knowledge

The longer Jorge waited in line at the ticket counter, the more his exasperation grew.

irritation

The state of being irritated.

Electronics Information

The valence shell of n insulator is how full of electrons?

more than half full

Insulators have valence shells that are more than half full of electrons and, as such, are tightly bound to the nucleus and difficult to move from one atom to another.

Word Knowledge

Placebo most nearly means:

sugar pill

An inactive substance used in medical testing.

General Science

pH is a scale that measures of how basic or acidic a solution is. A solution with a pH of 9 is:

alkaline

An acid is a substance that gives up positively charged hydrogen ions (H⁺) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH^-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.

Math Knowledge

The dimensions of this cube are height (h) = 7, length (l) = 7, and width (w) = 7. What is the surface area?

294

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 7 x 7) + (2 x 7 x 7) + (2 x 7 x 7)
sa = (98) + (98) + (98)
sa = 294

Mechanical Comprehension

What defines the mechanical advantage of a first class lever?

position of the fulcrum

A first-class lever is used to increase force or distance while changing the direction of the force. The lever pivots on a fulcrum and, when a force is applied to the lever at one side of the fulcrum, the other end moves in the opposite direction. The position of the fulcrum also defines the mechanical advantage of the lever. If the fulcrum is closer to the force being applied, the load can be moved a greater distance at the expense of requiring a greater input force. If the fulcrum is closer to the load, less force is required but the force must be applied over a longer distance. An example of a first-class lever is a seesaw / teeter-totter.

Mechanical Comprehension

The force amplification achieved by using a tool, mechanical device or machine system is called:

mechanical advantage

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction.

Math Knowledge

Which of the following is not required to define the slope-intercept equation for a line?

x-intercept

A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.