ASVAB Mechanical Comprehension Practice Test 65449 Results

Your Results Global Average
Questions 5 5
Correct 0 3.21
Score 0% 64%

Review

1

Which of the following is not a modulus of elasticity?

47% Answer Correctly

bulk modulus

stress modulus

stretch modulus

shear modulus


Solution

The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).


2

On Earth, acceleration due to gravity (g) is approximately __________. 

81% Answer Correctly

1 m/s2

9.8 m/s2

1 m/s

6.67 x 10-11 m/s2


Solution

Newton's Law of Univeral Gravitation defines the general formula for the attraction of gravity between two objects:  \(\vec{F_{g}} = { Gm_{1}m_{2} \over r^2}\) . In the specific case of an object falling toward Earth, the acceleration due to gravity (g) is approximately 9.8 m/s2. 


3

What type of load is sudden and for a relatively short duration?

69% Answer Correctly

non-uniformly distributed load

dynamic load

impact load

concentrated load


Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.


4 If the force applied at the blue arrow over 5 ft. moves the green box 0.56 ft., what is the mechanical advantage of this lever?
55% Answer Correctly
13.5
4
10
9

Solution

Mechanical advantage (MA) can be calculated knowing only the distance the effort (blue arrow) moves and the distance the resistance (green box) moves. The equation is:

MA = \( \frac{E_d}{R_d} \)

where Ed is the effort distance and Rd is the resistance distance. For this problem, the equation becomes:

MA = \( \frac{5 ft.}{0.56 ft.} \) = 9

You might be wondering how having an effort distance of 9 times the resistance distance is an advantage. Remember the principle of moments. For a lever in equilibrium the effort torque equals the resistance torque. Because torque is force x distance, if the effort distance is 9 times the resistance distance, the effort force must be \( \frac{1}{9} \) the resistance force. You're trading moving 9 times the distance for only having to use \( \frac{1}{9} \) the force.


5

Which of the following is not a characteristic of a ceramic?

61% Answer Correctly

low density

chemically stable

low corrosive action

high melting point


Solution

Ceramics are mixtures of metallic and nonmetallic elements that withstand exteme thermal, chemical, and pressure environments. They have a high melting point, low corrosive action, and are chemically stable. Examples include rock, sand, clay, glass, brick, and porcelain.