ASVAB Mechanical Comprehension Practice Test 116797 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.00
Score	0%	60%

Review

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

59% Answer Correctly

	mechanical advantage
	work done
	efficiency
	power conversion

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.

Which of the following surfaces would have the lowest coefficient of friction?

86% Answer Correctly

	ice
	leather
	tile
	concrete

Solution

Coefficient of friction (μ) represents how much two materials resist sliding across each other. Smooth surfaces like ice have low coefficients of friction while rough surfaces like concrete have high μ.

Which class of lever is used to increase force on an object in the same direction as the force is applied?

53% Answer Correctly

	first
	all of these
	third
	second

Solution

A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.

4 How much work can a 6 hp engine do in 10 seconds?

53% Answer Correctly

	1 ft⋅lb
	12 ft⋅lb
	33000 ft⋅lb
	0 ft⋅lb

Solution

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 6 hp \times 550 \frac{ft⋅lb}{s} \times 10s = 33000 ft⋅lb \)

Which of the following represents the force a surface exerts when an object presses against it?

49% Answer Correctly

	friction
	counter force
	normal force
	mass

Solution

Normal force (F_N) represents the force a surface exerts when an object presses against it.