Free ASVAB Practice Tests | ASVAB Test Bank

Mechanical Comprehension

If the green box weighs 20 lbs. and is 1 ft. from the fulcrum, how far from the fulcrum would a 70 lbs. force need to be applied to balance the lever?

0.29 ft.

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

R_ad_a = R_bd_b

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for d_b, our missing value, and plugging in our variables yields:

d_b = \( \frac{R_ad_a}{R_b} \) = \( \frac{20 lbs. \times 1 ft.}{70 lbs.} \) = \( \frac{20 ft⋅lb}{70 lbs.} \) = 0.29 ft.

Electronics Information

In household electrical wiring, which color of insulation indicates the 'hot' wire?

black

In the NM cable used for wiring homes, each cable has three wires inside a sheath with each wire covered in a different color of insulation to indicate its type. The wire with the black insulation is the 'hot' wire, white is the neutral wire, and the ground wire is either covered in green insulation or left bare.

Math Knowledge

Simplify 7a x 6b.

42ab

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

7a x 6b = (7 x 6) (a x b) = 42ab

Electronics Information

What is the frequency of most household electrical systems?

60Hz

Electricity is delivered from power stations to customers as AC because it provides a more efficient way to transport electricity over long distances. Most households use electricity with a frequency of 60Hz.

Electronics Information

Which of the following will increase the magnetic field produced by the electric current in a wire?

wind the wire into a coil

A moving electric current produces a magnetic field proportional to the amount of current flow. This magnetic field can be made stronger by winding the wire into a coil and further enhanced if done around an iron containing (ferrous) core.

Automotive Information

The stoichiometric ratio is approximately:

14.7:1

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.

Mechanical Comprehension

The standard unit of energy is the:

Joule

The Joule (J) is the standard unit of energy and has the unit \({kg \times m^2} \over s^2\).

General Science

In taxonomy, domains are the broadest classification of life. How many domains are there?

The broadest classification of life splits all organisms into three groups called domains. The three domains of life are bacteria, archaea and eukaryota.

General Science

An endoskeleton (internal skeleton) is a charateristic of __________ animals, including humans.

vertebrate

An endoskeleton (internal skeleton) is a charateristic of vertebrate animals, including humans.

Word Knowledge

Colossal most nearly means:

gigantic

Immense, enormous.