ASVAB Mechanical Comprehension Practice Test 29725 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.63
Score	0%	53%

Review

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

57% Answer Correctly

	parallel to
	opposite to
	perpendicular to
	along

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.

2 How much work can a 7 hp engine do in 8 seconds?

52% Answer Correctly

	30800 ft⋅lb
	1 ft⋅lb
	14 ft⋅lb
	3 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:
\( W = 7 hp \times 550 \frac{ft⋅lb}{s} \times 8s = 30800 ft⋅lb \)

Which of the following statements about this pulley configuration is false?

48% Answer Correctly

	Changes the direction of and multiplies the effort force
	Mechanical advantage is the number of ropes that support the resistance
	Only multiplies the effort force
	This is a block and tackle pulley configuration

Solution

A block and tackle is a combination of one or more fixed pulleys and one or more movable pulleys where the fixed pulleys change the direction of the effort force and the movable pulleys multiply it. The mechanical advantage is equal to the number of times the effort force changes direction and can be increased by adding more pulley wheels to the system. An easy way to find the mechanical advantage of a block and tackle pulley system is to count the number of ropes that support the resistance.

Which of the following is not a modulus of elasticity?

47% Answer Correctly

	stress modulus
	bulk modulus
	shear modulus
	stretch modulus

Solution

The modulus of elasticity measures how much a material or structure will deflect under stress. Stretch modulus is longitudinal stretch (like stretching raw bread dough), shear modulus is longitudinal deflection (like the horizontal displacement of a stack of magzines when a heavy object is placed upon them), and bulk modulus is compression of volume (like the compression of a loaf of bread under a heavy can at the bottom of a grocery bag).

Which of the following statements about drag is false?

58% Answer Correctly

	the amount of drag depends on the shape of an object
	drag occurs during movement through a fluid
	slower objects experience more drag than faster objects
	the amount of drag depends on the speed of an object

Solution

Drag is friction that opposes movement through a fluid like liquid or air. The amount of drag depends on the shape and speed of the object with slower objects experiencing less drag than faster objects and more aerodynamic objects experiencing less drag than those with a large leading surface area.