ASVAB Mechanical Comprehension Practice Test 775764 Results

Your Results Global Average
Questions 5 5
Correct 0 3.32
Score 0% 66%

Review

1

The work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. This defines which of the following?

60% Answer Correctly

work-energy theorem

conservation of mechanical energy

mechanical advantage

Pascal's law
Solution

The work-energy theorem states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particle. Simply put, work imparts kinetic energy to the matter upon which the work is being done.

2 If input effort is 900 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 2?
79% Answer Correctly
0ft⋅lb
1800 ft⋅lb
900ft⋅lb
3600ft⋅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 900 ft⋅lb by 2 to produce an output effort of 1800 ft⋅lb.
3

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

80% Answer Correctly

mechanical advantage

work

efficiency

power
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.

4 If the green box weighs 10 lbs. and is 9 ft. from the fulcrum, how far from the fulcrum would a 65 lbs. force need to be applied to balance the lever?
58% Answer Correctly
2.77 ft.
1.38 ft.
0 ft.
0.46 ft.
Solution

To balance this lever the torques at the green box and the blue arrow must be equal. Torque is weight x distance from the fulcrum so the equation for equilibrium is:

Rada = Rbdb

where a represents the green box and b the blue arrow, R is resistance (weight/force) and d is the distance from the fulcrum.

Solving for db, our missing value, and plugging in our variables yields:

db = \( \frac{R_ad_a}{R_b} \) = \( \frac{10 lbs. \times 9 ft.}{65 lbs.} \) = \( \frac{90 ft⋅lb}{65 lbs.} \) = 1.38 ft.

5

Concurrent forces:

55% Answer Correctly

act along the same line of action

act in a common dimension

pass through a common point

act in a common plane
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.