ASVAB Mechanical Comprehension Practice Test 474754 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.29
Score	0%	66%

Review

1 How much work can a 4 hp engine do in 6 seconds?

52% Answer Correctly

	0 ft⋅lb
	16 ft⋅lb
	13200 ft⋅lb
	1 ft⋅lb

Solution

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 4 hp \times 550 \frac{ft⋅lb}{s} \times 6s = 13200 ft⋅lb \)

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

73% Answer Correctly

	kinetic friction
	dynamic friction
	static friction
	gravitational 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.

Which class of lever is used to increase force on an object in the same direction as the force is applied?

52% Answer Correctly

	third
	first
	all of these
	second

Solution

A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.

Collinear forces:

72% Answer Correctly

	act along the same line of action
	pass through a common point
	act in a common plane
	are unrelated to each other

Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

5 If input effort is 400 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 2?

79% Answer Correctly

	3200ft⋅lb
	1600ft⋅lb
	800 ft⋅lb
	200ft⋅lb

Solution

Mechanical advantage is the ratio of output force to input force and tells us by how many times a machine multiplies input effort. So, a machine with a mechanical advantage of 2 will multiply an input effort of 400 ft⋅lb by 2 to produce an output effort of 800 ft⋅lb.