ASVAB Mechanical Comprehension Practice Test 57625 Results

Your Results Global Average
Questions 5 5
Correct 0 3.51
Score 0% 70%

Review

1 If input effort is 800 ft⋅lb, what output effort will be produced by a machine with a mechanical advantage of 7?
79% Answer Correctly
5600 ft⋅lb
11200ft⋅lb
2800ft⋅lb
0ft⋅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 7 will multiply an input effort of 800 ft⋅lb by 7 to produce an output effort of 5600 ft⋅lb.
2

Two gears are connected and the smaller gear drives the larger gear. The speed of rotation will __________ and the torque will __________.

61% Answer Correctly

increase, decrease

increase, increase

decrease, decrease

decrease, increase
Solution

Connected gears of different numbers of teeth are used together to change the rotational speed and torque of the input force. If the smaller gear drives the larger gear, the speed of rotation will be reduced and the torque will increase. If the larger gear drives the smaller gear, the speed of rotation will increase and the torque will be reduced.

3 If the green box weighs 65 lbs. and is 9 ft. from the fulcrum, how far from the fulcrum would a 50 lbs. force need to be applied to balance the lever?
58% Answer Correctly
585 ft.
7 ft.
11.7 ft.
2.93 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 = \( \frac{R_ad_a}{R_b} \) = \( \frac{65 lbs. \times 9 ft.}{50 lbs.} \) = \( \frac{585 ft⋅lb}{50 lbs.} \) = 11.7 ft.

4

Which of the following is not a type of bridge?

74% Answer Correctly

block

arch

cable

truss
Solution

The six basic bridge forms are beam, truss, arch, cantilever, cable, and suspension.

5

Drag is a type of:

81% Answer Correctly

work

friction

kinetic energy

potential energy
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.