ASVAB Mechanical Comprehension Practice Test 699022 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.14
Score	0%	63%

Review

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

58% Answer Correctly

	gear
	screw
	lever
	pulley

Solution

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

Which class of lever offers no mechanical advantage?

45% Answer Correctly

	none of these, all levers offer mechanical advantage
	third
	second
	first

Solution

A third-class lever is used to increase distance traveled by an object in the same direction as the force applied. The fulcrum is at one end of the lever, the object at the other, and the force is applied between them. This lever does not impart a mechanical advantage as the effort force must be greater than the load but does impart extra speed to the load. Examples of third-class levers are shovels and tweezers.

3 If the green arrow in this diagram represents 350 ft⋅lb of work, how far will the box move if it weighs 70 pounds?

72% Answer Correctly

	14 ft.
	35 ft.
	17 ft.
	5 ft.

Solution

The Law of Work states that the work put into a machine is equal to the work received from the machine under ideal conditions. In equation form, that's:

W_in = W_out
F_effort x d_effort = F_resistance x d_resistance

In this problem, the effort work is 350 ft⋅lb and the resistance force is 70 lbs. and we need to calculate the resistance distance:

W_in = F_resistance x d_resistance
350 ft⋅lb = 70 lbs. x d_resistance
d_resistance = \( \frac{350ft⋅lb}{70 lbs.} \) = 5 ft.

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.

What is the first step to solving a problem where multiple forces are acting on an object?

61% Answer Correctly

	calculate the net force
	calculate potential energy
	calculate the total force
	calculate kinetic energy

Solution

In mechanics, multiple forces are often acting on a particular object and, taken together, produce the net force acting on that object. Like force, net force is a vector quantity in that it has magnitude and direction.