ASVAB Mechanical Comprehension Practice Test 767542 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.19
Score	0%	64%

Review

Concurrent forces:

55% Answer Correctly

	act in a common plane
	act in a common dimension
	pass through a common point
	act along the same line of action

Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

What type of load varies with time or affects a structure that experiences a high degree of movement?

65% Answer Correctly

	concentrated load
	impact load
	static load
	dynamic 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.

Friction between two or more solid objects that are not moving relative to each other is called:

73% Answer Correctly

	static friction
	kinetic friction
	dynamic friction
	gravitational friction

Solution

Static friction is friction between two or more solid objects that are not moving relative to each other. An example is the friction that prevents a box on a sloped surface from sliding farther down the surface.

4 What is the efficiency of a machine has work input of 125 ft⋅lb and work output of 56 ft⋅lb?

67% Answer Correctly

	45%
	55%
	0%
	180%

Solution

Due to friction, a machine will never be able to utilize 100% of its work input. A certain percentage of that input will be lost in overcoming friction within the machine. Effeciency is a measure of how much of a machine's work input can be turned into useful work output and is calculated by dividing work output by work input and multiplying the result by 100:
\( Efficiency = \frac{Work_{out}}{Work_{in}} \times 100 \) \( = \frac{56 ft⋅lb}{125 ft⋅lb} \times 100 \) \( = 45% \) %

Gear ratio indicates which of the following about two connected gears?

59% Answer Correctly

	power conversion
	efficiency
	mechanical advantage
	work done

Solution

The mechanical advantage (amount of change in speed or torque) of connected gears is proportional to the number of teeth each gear has. Called gear ratio, it's the ratio of the number of teeth on the larger gear to the number of teeth on the smaller gear. For example, a gear with 12 teeth connected to a gear with 9 teeth would have a gear ratio of 4:3.