ASVAB Mechanical Comprehension Practice Test 975924 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.93
Score	0%	59%

Review

Which of the following is not a type of simple machine?

58% Answer Correctly

	screw
	lever
	gear
	pulley

Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

2 What is the power output of a 1 hp engine that's 30% efficient?

39% Answer Correctly

	660 \( \frac{ft⋅lb}{s} \)
	41.3 \( \frac{ft⋅lb}{s} \)
	82.5 \( \frac{ft⋅lb}{s} \)
	165 \( \frac{ft⋅lb}{s} \)

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 1 hp x 550 \( \frac{ft⋅lb}{s} \) = 550 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{30 \times 550 \frac{ft⋅lb}{s}}{100} \) \( = \frac{16500 \frac{ft⋅lb}{s}}{100} \) = 165 \( \frac{ft⋅lb}{s} \)

What is work?

60% Answer Correctly

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

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

70% Answer Correctly

	weight
	mass
	density
	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.

A box is resting on a smooth floor. Static friction is present:

59% Answer Correctly

	if the coefficient of friction is greater than one
	at all times
	when an attempt is made to move the box
	only if normal force is present

Solution

For any given surface, the coefficient of static friction is higher than the coefficient of kinetic friction. More force is required to initally get an object moving than is required to keep it moving. Additionally, static friction only arises in response to an attempt to move an object (overcome the normal force between it and the surface).