ASVAB Mechanical Comprehension Practice Test 256988 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.08
Score	0%	62%

Review

1 If the handles of a wheelbarrow are 2.0 ft. from the wheel axle and the load is concentrated at a point 1.5 ft. from the axle, how many pounds of load will a 220 lbs. force lift?

47% Answer Correctly

	73.3
	330
	293.3
	-12

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: F_ed_e = F_rd_r. In this problem we're looking for resistance force:
\( F_r = \frac{F_e d_e}{d_r} \)
\( F_r = \frac{220 \times 2.0}{1.5} \)
\( F_r = \frac{440.0}{1.5} \)
\( F_r = 293.3 \)

Which of the following is not a type of simple machine?

58% Answer Correctly

	gear
	lever
	screw
	pulley

Solution

The six types of simple machines are the lever, wheel and axle, pulley, inclined plane, wedge, and screw.

3 If the radius of the axle is 7 and the radius of the wheel is 8, what is the mechanical advantage of this wheel and axle configuration?

52% Answer Correctly

	1.14
	-1
	1
	0.88

Solution

The mechanical advantage of a wheel and axle is the input radius divided by the output radius:

MA = \( \frac{r_i}{r_o} \)

In this case, the input radius (where the effort force is being applied) is 8 and the output radius (where the resistance is being applied) is 7 for a mechanical advantage of \( \frac{8}{7} \) = 1.14

A watt is the unit for which of the following?

71% Answer Correctly

	energy
	mechanical advantage
	work
	power

Solution

Power is the rate at which work is done, P = w/t, or work per unit time. The watt (W) is the unit for power and is equal to 1 joule (or newton-meter) per second. Horsepower (hp) is another familiar unit of power used primarily for rating internal combustion engines. 1 hp equals 746 watts.

A block and tackle with four pulleys would have a mechanical advantage of:

79% Answer Correctly

	1
	2
	0
	4

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.