ASVAB Mechanical Comprehension Practice Test 947043 Results

	Your Results	Global Average
Questions	5	5
Correct	0	2.76
Score	0%	55%

Review

Boyle's law defines the relationship between pressure and volume as:

58% Answer Correctly

	\(\frac{P_1}{P_2} = {V_1}{V_2}\)
	\({P_1}{P_2} = {V_1}{V_2}\)
	\(\frac{P_1}{P_2} = \frac{V_1}{V_2}\)
	\(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)

Solution

Boyle's law states that "for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional". Expressed as a formula, that's \(\frac{P_1}{P_2} = \frac{V_2}{V_1}\)

Assuming force applied remains constant, which of the following will result in more work being done?

53% Answer Correctly

	increasing the coefficient of friction
	moving the object with more speed
	moving the object with more acceleration
	moving the object farther

Solution

Work is accomplished when force is applied to an object: W = Fd where F is force in newtons (N) and d is distance in meters (m). Thus, the more force that must be applied to move an object, the more work is done and the farther an object is moved by exerting force, the more work is done.

3 How much work can a 3 hp engine do in 2 seconds?

53% Answer Correctly

	3300 ft⋅lb
	6 ft⋅lb
	12 ft⋅lb
	0 ft⋅lb

Solution

Horsepower (hp) is a common measure of power output for complex machines. By definition, a 1 hp machine does 550 ft⋅lb of work in 1 second: 1 hp = 550 ft⋅lb/s. Substituting the variables for this problem gives us:
\( W = 3 hp \times 550 \frac{ft⋅lb}{s} \times 2s = 3300 ft⋅lb \)

Which class of lever is used to increase force on an object in the same direction as the force is applied?

53% Answer Correctly

	second
	first
	all of these
	third

Solution

A second-class lever is used to increase force on an object in the same direction as the force is applied. This lever requires a smaller force to lift a larger load but the force must be applied over a greater distance. The fulcrum is placed at one end of the lever and mechanical advantage increases as the object being lifted is moved closer to the fulcrum or the length of the lever is increased. An example of a second-class lever is a wheelbarrow.

Which of the following statements about drag is false?

58% Answer Correctly

	drag occurs during movement through a fluid
	the amount of drag depends on the speed of an object
	slower objects experience more drag than faster objects
	the amount of drag depends on the shape of an object

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.