ASVAB Mechanical Comprehension Practice Test 881849 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.41
Score	0%	68%

Review

The science that deals with motion and the forces that produce motion is called which of the following?

57% Answer Correctly

	physics
	mechanics
	aeronautics
	engineering

Solution

Mechanics deals with motion and the forces that produce motion.

The force exerted on an object due to gravity is called:

69% Answer Correctly

	density
	mass
	weight
	potential energy

Solution

Mass is an intrinsic property of matter and does not vary. Weight is the force exerted on the mass of an object due to gravity and a specific case of Newton's Second Law of Motion. Replace force with weight and acceleration with acceleration due to gravity on Earth (g) and the result is the formula for weight: W = mg or, substituting for g, weight equals mass multiplied by 9.8 m/s².

3 If you have a gear train with two gears, the first with 24 teeth and the second with 16 teeth, how many revolutions does the second gear make for each revolution of the first gear?

77% Answer Correctly

	0.8
	1.5
	3
	4.5

Solution

The gear ratio (V_r) of a gear train is the product of the gear ratios between the pairs of meshed gears. Let N represent the number of teeth for each gear:

V_r = \( \frac{N_1}{N_2} \) \( \frac{N_2}{N_3} \) \( \frac{N_3}{N_4} \) ... \( \frac{N_n}{N_{n+1}} \)

In this problem, we have only two gears so the equation becomes:

V_r = \( \frac{N_1}{N_2} \) = \( \frac{24}{16} \) = 1.5

The measure of how much of the power put into a machine is turned into movement or force is called:

56% Answer Correctly

	efficiency
	power
	mechanical advantage
	force multiplication

Solution

The efficiency of a machine describes how much of the power put into the machine is turned into movement or force. A 100% efficient machine would turn all of the input power into output movement or force. However, no machine is 100% efficient due to friction, heat, wear and other imperfections that consume input power without delivering any output.

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

85% Answer Correctly

	tile
	leather
	ice
	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.