ASVAB Mechanical Comprehension Practice Test 465146 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.05
Score	0%	61%

Review

A wedge converts force applied to its blunt end into force __________ its inclined surface.

57% Answer Correctly

	perpendicular to
	opposite to
	along
	parallel to

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.

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

	near the truck
	near the car
	in the middle
	tension is equal in all parts of the rope

Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.

3 What is the mechanical advantage of this inclined plane if the length of the ramp is 4 ft. and the height of the green box is 2 ft.?

82% Answer Correctly

	6
	5
	3
	2

Solution

The mechanical advantage (MA) of an inclined plane is the effort distance divided by the resistance distance. In this case, the effort distance is the length of the ramp and the resistance distance is the height of the green box:

MA = \( \frac{d_e}{d_r} \) = \( \frac{4 ft.}{2 ft.} \) = 2

Friction between two or more solid objects that are not moving relative to each other is called:

74% Answer Correctly

	gravitational friction
	kinetic friction
	static friction
	dynamic friction

Solution

Static friction is friction between two or more solid objects that are not moving relative to each other. An example is the friction that prevents a box on a sloped surface from sliding farther down the surface.

5 What is the power output of a 5 hp engine that's 45% efficient?

40% Answer Correctly

	412.5 \( \frac{ft⋅lb}{s} \)
	0 \( \frac{ft⋅lb}{s} \)
	309.4 \( \frac{ft⋅lb}{s} \)
	1237.5 \( \frac{ft⋅lb}{s} \)

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 5 hp x 550 \( \frac{ft⋅lb}{s} \) = 2750 \( \frac{ft⋅lb}{s} \)
\( P_{o} = \frac{E \times P_{i}}{100} = \frac{45 \times 2750 \frac{ft⋅lb}{s}}{100} \) \( = \frac{123750 \frac{ft⋅lb}{s}}{100} \) = 1237.5 \( \frac{ft⋅lb}{s} \)