ASVAB Mechanical Comprehension Practice Test 556821 Results

Your Results Global Average
Questions 5 5
Correct 0 3.25
Score 0% 65%

Review

1

If the handles of a wheelbarrow are 3 ft. from the wheel axle, what force must you exert to lift the handles if it's carrying a 270 lb. load concentrated at a point 0.5 ft. from the axle?

56% Answer Correctly

810 lbs

90 lbs

45 lbs

0.83 lbs
Solution

This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: Fede = Frdr. Plugging in the variables from this problem yields:

Fe x 3 ft. = 270 lbs x 0.5 ft
Fe = 135 ft-lb. / 3 ft 
Fe = 45 lbs

2

The mechanical advantage of a block and tackle is equal to which of the following?

69% Answer Correctly

the number of input forces

the number of loads

the number of connecting ropes

the number of pulleys
Solution

Two or more pulleys used together constitute a block and tackle which, unlike a fixed pulley, does impart mechanical advantage as a function of the number of pulleys that make up the arrangement.  So, for example, a block and tackle with three pulleys would have a mechanical advantage of three.

3 A 410 lb. barrel is rolled up a 7 ft. ramp to a platform that's 3 ft. tall. What effort is required to move the barrel?
53% Answer Correctly
158.1 lbs.
263.6 lbs.
175.7 lbs.
193.3 lbs.
Solution

This problem describes an inclined plane and, for an inclined plane, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance:

Fede = Frdr

Plugging in the variables from this problem yields:

Fe x 7 ft. = 410 lbs. x 3 ft.
Fe = \( \frac{1230 ft⋅lb}{7 ft.} \) = 175.7 lbs.

4 If you lift a 50 lbs. rock 35 ft. from the ground, how much work have you done?
71% Answer Correctly
875 ft⋅lb
1750 ft⋅lb
1 ft⋅lb
0 ft⋅lb
Solution
Work is force times distance. In this case, the force is the weight of the rock so:
\( W = F \times d \)
\( W = 50 \times 35 \)
\( W = 1750 \)
5

Which of the following is not a type of bridge?

74% Answer Correctly

cable

block

arch

truss
Solution

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