ASVAB Mechanical Comprehension Practice Test 585369 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.53
Score	0%	71%

Review

1 What's the mechanical advantage of a wedge that's 3 inches wide and 21 inches long?

83% Answer Correctly

	2
	21
	10.5
	7

Solution

The mechanical advantage (MA) of a wedge is its length divided by its thickness:

MA = \( \frac{l}{t} \) = \( \frac{21 in.}{3 in.} \) = 7

2 If the force applied at the blue arrow over 3 ft. moves the green box 1.5 ft., what is the mechanical advantage of this lever?

56% Answer Correctly

	3
	2
	1
	-6

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 E_d is the effort distance and R_d is the resistance distance. For this problem, the equation becomes:

MA = \( \frac{3 ft.}{1.5 ft.} \) = 2

You might be wondering how having an effort distance of 2 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 2 times the resistance distance, the effort force must be \( \frac{1}{2} \) the resistance force. You're trading moving 2 times the distance for only having to use \( \frac{1}{2} \) the force.

Two or more pulleys used together are called:

71% Answer Correctly

	block and tackle
	third-class lever
	wheel and axle
	gears

Solution

Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement. So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.

Which of these is the formula for force?

77% Answer Correctly

	F = m/a
	F = am²
	F = ma
	F = a/m

Solution

Newton's Second Law of Motion states that "The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object." This Law describes the linear relationship between mass and acceleration when it comes to force and leads to the formula F = ma or force equals mass multiplied by rate of acceleration.

When it comes to force, mass and acceleration have what kind of relationship?

66% Answer Correctly

	exponential
	inverse
	linear
	logarithmic