ASVAB Mechanical Comprehension Practice Test 762530 Results

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

Review

A wedge is most similar to what other type of simple machine?

70% Answer Correctly

	second-class lever
	third-class lever
	first-class lever
	inclined plane

Solution

The wedge is a moving inclined plane that is used to lift, hold, or break apart an object. A wedge converts force applied to its blunt end into force perpendicular to its inclined surface. In contrast to a stationary plane where force is applied to the object being moved, with a wedge the object is stationary and the force is being applied to the plane. Examples of a wedge include knives and chisels.

What is work?

60% Answer Correctly

	Force per unit distance
	The potential for exertion
	The movement of an object by a force
	Force per unit time

Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done. By definition, work is the displacement of an object resulting from applied force.

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

61% Answer Correctly

	low corrosive action
	low density
	high melting point
	chemically stable

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.

4 What is the power output of a 4 hp engine that's 55% efficient?

39% Answer Correctly

	0 \( \frac{ft⋅lb}{s} \)
	2420 \( \frac{ft⋅lb}{s} \)
	1210 \( \frac{ft⋅lb}{s} \)
	4840 \( \frac{ft⋅lb}{s} \)

Solution

\( Efficiency = \frac{Power_{out}}{Power_{in}} \times 100 \)
Solving for power out: \( P_{o} = \frac{E \times P_{i}}{100} \)
Knowing that 1 hp = 550 \( \frac{ft⋅lb}{s} \), P_i becomes 4 hp x 550 \( \frac{ft⋅lb}{s} \) = 2200 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{55 \times 2200 \frac{ft⋅lb}{s}}{100} \) \( = \frac{121000 \frac{ft⋅lb}{s}}{100} \) = 1210 \( \frac{ft⋅lb}{s} \)

The mechanical advantage of a block and tackle is equal to which of the following?

69% Answer Correctly

	the number of pulleys
	the number of connecting ropes
	the number of input forces
	the number of loads

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.