ASVAB Mechanical Comprehension Practice Test 271321 Results

Your Results Global Average
Questions 5 5
Correct 0 2.95
Score 0% 59%

Review

1

The force required to initally get an object moving is __________ the force required to keep it moving. 

76% Answer Correctly

lower than

opposite

higher than

the same as
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).

2 How much work can a 1 hp engine do in 5 seconds?
52% Answer Correctly
2750 ft⋅lb
0 ft⋅lb
2 ft⋅lb
4 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:
\( W = 1 hp \times 550 \frac{ft⋅lb}{s} \times 5s = 2750 ft⋅lb \)
3

Which of the following is not a modulus of elasticity?

47% Answer Correctly

shear modulus

bulk modulus

stretch modulus

stress 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).

4

The force amplification achieved by using a tool, mechanical device or machine system is called:

80% Answer Correctly

work

power

mechanical advantage

efficiency
Solution

Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Such a device utilizes input force and trades off forces against movement to amplify and/or change its direction.

5

Force of friction due to kinetic friction is __________ the force of friction due to static friction.

40% Answer Correctly

the same as

opposite

higher than

lower than
Solution

The formula for force of friction (Ff) is the same whether kinetic or static friction applies: Ff = μFN. To distinguish between kinetic and static friction, μk and μs are often used in place of μ.