OAR (Officer Aptitude Rating) Test — Questions and Answers

Question 1: Read the following passage and answer the question: "The principle of buoyancy, first described by Archimedes, states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces. A ship, despite being constructed from tons of steel which is far denser than water, floats because its hull is shaped to displace a large volume of water. If the weight of the displaced water is greater than the total weight of the ship, the ship floats. If it is less, the ship sinks." Based on the passage, what can be inferred about a submarine's ability to submerge and surface?

It relies solely on propellers to push it underwater.
It must have a method to alter its own weight or the volume of water it displaces. (Correct answer)
It must be made of a material less dense than water.
It sinks because its shape is not like a traditional ship's hull.

Correct answer: It must have a method to alter its own weight or the volume of water it displaces.

The passage explains that floating is a balance between the ship's weight and the weight of the water it displaces. To submerge (sink) and surface (float) at will, a submarine must be able to control this balance. This implies it can change its own weight (by taking in or expelling water in ballast tanks) to become heavier or lighter than the water it displaces. The other options misinterpret the core principle described.

Question 2: A historian writes: 'The treaty was signed in June, yet by September, both nations had doubled their military spending and repositioned troops along the border.' What can you infer about the treaty?

The treaty focused on trade rather than military matters
It successfully established lasting peace
It was likely ineffective at reducing tensions between the nations (Correct answer)
Both nations were preparing for a joint military exercise

Correct answer: It was likely ineffective at reducing tensions between the nations

Increased military spending and troop repositioning shortly after signing suggest the treaty failed to ease hostilities.

Question 3: An editorial states: 'Despite receiving the largest budget allocation in the department's history, test scores remained unchanged for the third consecutive year.' What is the author most likely implying?

Increased funding alone has not improved educational outcomes (Correct answer)
The department managed its budget efficiently
The budget should be increased even further
Test scores are an unreliable measure of success

Correct answer: Increased funding alone has not improved educational outcomes

By juxtaposing record funding with stagnant results, the author implies that more money alone is not solving the problem.

Question 4: A 500 N person stands on a scale in an elevator accelerating upward at 2 m/s². What does the scale read? (g ≈ 10 m/s²)

400 N
600 N (Correct answer)
500 N
1000 N

Correct answer: 600 N

Mass = 50 kg; scale reads N = m(g + a) = 50(10 + 2) = 600 N.

Question 5: A report notes that a pharmaceutical company fast-tracked clinical trials, skipping the typical Phase II testing, and the FDA issued an unusual number of post-market safety warnings for the resulting drug. What inference is most supported?

The drug was unnecessarily delayed by regulators
Phase II testing is generally considered unnecessary
Skipping Phase II testing may have allowed safety issues to go undetected before release (Correct answer)
The FDA warnings were unrelated to the shortened trials

Correct answer: Skipping Phase II testing may have allowed safety issues to go undetected before release

Bypassing a standard testing phase followed by multiple safety warnings suggests the skipped phase would have caught those issues.

Question 6: A trapezoid has parallel bases of 10 ft and 6 ft, and a height of 4 ft. What is its area?

24 ft²
32 ft² (Correct answer)
64 ft²
40 ft²

Correct answer: 32 ft²

Area = ½ × (b₁ + b₂) × h = ½ × 16 × 4 = 32 ft².

Question 7: Simplify: (2x + 3)(x - 4)

2x² + 5x - 12
2x² - 5x + 12
2x² - x - 12
2x² - 5x - 12 (Correct answer)

Correct answer: 2x² - 5x - 12

FOIL: 2x² - 8x + 3x - 12 = 2x² - 5x - 12.

Question 8: Water flows through a horizontal pipe that narrows from a diameter of 4 cm to 2 cm. How does the flow velocity change in the narrow section?

It stays the same
It quadruples (Correct answer)
It doubles
It halves

Correct answer: It quadruples

By the continuity equation, velocity is inversely proportional to cross-sectional area, and halving the diameter reduces area by a factor of four, so velocity quadruples.

Question 9: Read: 'Deep-sea exploration has revealed ecosystems thriving without sunlight, powered instead by chemical energy from hydrothermal vents. These organisms challenge long-held assumptions about the requirements for life. Scientists now consider such environments when searching for life on other planets.' The main idea is:

Discoveries of sunlight-independent life have expanded our understanding of where life can exist. (Correct answer)
Deep-sea life forms survive by photosynthesis in dark conditions.
Hydrothermal vents are found only in the Pacific Ocean.
NASA funds all deep-sea exploration missions.

Correct answer: Discoveries of sunlight-independent life have expanded our understanding of where life can exist.

The passage is about how chemosynthetic life broadens the concept of habitable environments, including implications for astrobiology.

Question 10: A passage about naval history includes this sentence: 'The Battle of Midway in June 1942 marked a decisive turning point in the Pacific War.' Which question would most help a reader identify supporting details for this claim?

How many sailors served in the U.S. Navy during World War II?
What other battles took place in 1942?
When did World War II begin and end?
What specific outcomes of the battle changed the course of the Pacific War? (Correct answer)

Correct answer: What specific outcomes of the battle changed the course of the Pacific War?

Asking about specific outcomes that shifted the war's direction would yield details that directly support the claim about a turning point.

Question 11: A storage facility charges $1.25 per square foot per month. If a unit measures 10 feet by 14 feet, what is the total cost for 6 months?

$875
$1,050 (Correct answer)
$950
$1,200

Correct answer: $1,050

The unit is 140 sq ft (10 × 14), costing $175/month (140 × $1.25), so 6 months costs $175 × 6 = $1,050.

Question 12: A dam holds back water 30 feet deep. At what depth below the surface is the pressure greatest?

At 30 feet (Correct answer)
At the surface
At 15 feet
Pressure is uniform throughout

Correct answer: At 30 feet

Hydrostatic pressure increases with depth (P = ρgh), so pressure is greatest at the bottom of the water column.

Question 13: In a fixed pulley system, what is the mechanical advantage?

Depends on rope length
2
0
1 (Correct answer)

Correct answer: 1

A single fixed pulley has a mechanical advantage of 1 — it changes direction of force but does not multiply it.

Question 14: Read the passage: 'The factory's output doubled after the new manager arrived. Overtime requests dropped, and employee surveys showed higher morale.' What can be inferred about the new manager's approach?

The manager reduced the number of employees on each shift.
The manager made changes that improved both efficiency and worker satisfaction. (Correct answer)
The manager increased working hours to boost production.
The manager focused solely on quality control rather than output.

Correct answer: The manager made changes that improved both efficiency and worker satisfaction.

Higher output alongside fewer overtime hours and better morale indicates the manager improved processes in ways that benefited both productivity and workers.

Question 15: A cylinder has a radius of 4 cm and a height of 9 cm. What is its volume in terms of pi?

72pi cu cm
108pi cu cm
36pi cu cm
144pi cu cm (Correct answer)

Correct answer: 144pi cu cm

Volume = pi*r^2*h = pi*16*9 = 144pi cu cm.

Question 16: Read the passage: 'The library's reference section had not been updated in over a decade. A student searching for recent census data found figures that were clearly outdated.' What can be inferred about the reliability of other resources in that section?

Only census data becomes outdated quickly; other reference materials remain accurate.
Other resources are likely also outdated and may be unreliable for current data. (Correct answer)
The library intentionally keeps older editions for historical research.
The student should have used a different section of the library.

Correct answer: Other resources are likely also outdated and may be unreliable for current data.

If the section has not been updated in over a decade and one resource is outdated, it is reasonable to infer other materials there may also be out of date.

Question 17: A 100 lb traffic light is suspended motionless by two cables. Cable A makes a 30-degree angle with the horizontal ceiling, and Cable B makes a 60-degree angle with the horizontal ceiling. Which cable experiences greater tension?

Cable B (the one with the larger angle to horizontal).
Cable A (the one with the smaller angle to horizontal). (Correct answer)
It is impossible to determine without knowing the cable lengths.
Both cables experience the same tension.

Correct answer: Cable A (the one with the smaller angle to horizontal).

For an object in equilibrium, the vertical components of the tension forces must sum to equal the object's weight. As the angle of a support cable becomes more horizontal (smaller angle with the horizontal), it must provide a much larger total tension to contribute the same amount of vertical lift. Therefore, Cable A, with the smaller angle of 30 degrees, will bear a significantly greater tension than Cable B.

Question 18: What does the term primer signify in this passage?

Painted binding agent
Small fuel pump (Correct answer)
Short, introductory guide
Explosive ignition cap

Correct answer: Small fuel pump

In the context of the passage (which is not provided), the term 'primer' signifies a small fuel pump. This device is typically used in internal combustion engines, particularly in aircraft or older vehicles, to manually inject a small amount of fuel into the engine cylinders to aid in starting, especially in cold conditions.

Question 19: A passage reads: 'The briefing was cursory, covering only the most salient points without elaborating on logistics or contingencies.' The word 'cursory' most nearly means:

Hasty and superficial (Correct answer)
Classified and restricted
Thorough and detailed
Repetitive and redundant

Correct answer: Hasty and superficial

'Cursory' means done quickly with little attention to detail, consistent with the briefing that skipped logistics and contingencies.

Question 20: A small company's monthly profit is given by the expression P = 150x - (85x + 2500), where x is the number of units sold. Which of the following is a simplified expression for the monthly profit?

P = 65x + 2500
P = 235x - 2500
P = 65x - 2500 (Correct answer)
P = 235x + 2500

Correct answer: P = 65x - 2500

To simplify the expression P = 150x - (85x + 2500), you must first distribute the negative sign to both terms within the parentheses. This changes the expression to P = 150x - 85x - 2500. Then, combine the like terms (the terms with x): 150x - 85x = 65x. The constant term remains -2500. Therefore, the simplified expression is P = 65x - 2500.

Question 21: Read the following passage and answer the question: "In the early 20th century, naval strategists developed 'dazzle camouflage' not to hide a ship, but to confuse the enemy. The complex patterns of intersecting geometric shapes in contrasting colors were designed to make it difficult for an enemy to estimate a ship's type, speed, and heading. An enemy submarine commander using a periscope would have a hard time determining exactly where to aim a torpedo. This form of camouflage was a response to the advent of long-range naval gunnery and torpedo attacks where targeting accuracy was paramount." Which of the following can be inferred from the passage?

The primary goal of this camouflage was deception rather than concealment. (Correct answer)
Dazzle camouflage was most effective at close ranges.
Dazzle camouflage was rendered obsolete by the invention of radar.
Before dazzle camouflage, all naval ships were painted gray.

Correct answer: The primary goal of this camouflage was deception rather than concealment.

The passage explicitly states that dazzle camouflage was not meant 'to hide a ship, but to confuse the enemy' about its speed and direction. This directly supports the inference that its goal was deception (misleading the enemy's judgment) rather than concealment (making the ship invisible). The other statements are either not supported or contradicted by the text.

Question 22: A project requires 6 officers working 8 hours per day for 10 days. If 2 officers are reassigned, how many hours per day must the remaining 4 work to finish on time?

10 hours
14 hours
11 hours
12 hours (Correct answer)

Correct answer: 12 hours

Total work = 6 x 8 x 10 = 480 officer-hours; hours per day = 480 / (4 x 10) = 12 hours.

Question 23: Water flows through a horizontal pipe that narrows at a certain point. According to Bernoulli's principle, what happens to the speed and pressure of the water as it passes through this constricted section?

The speed decreases and the pressure increases.
The speed increases and the pressure increases.
The speed increases and the pressure decreases. (Correct answer)
The speed decreases and the pressure decreases.

Correct answer: The speed increases and the pressure decreases.

Bernoulli's principle states that for a fluid in motion, an increase in speed occurs simultaneously with a decrease in pressure. As the pipe narrows, the principle of continuity dictates that the fluid must speed up to maintain the same volume flow rate. This increase in kinetic energy (speed) comes at the expense of pressure energy, so the pressure in the constricted section decreases.

Question 24: Two similar triangles have corresponding sides in a ratio of 3:5. If the area of the smaller triangle is 27 cm², what is the area of the larger triangle?

75 cm² (Correct answer)
50 cm²
45 cm²
135 cm²

Correct answer: 75 cm²

The area ratio equals the square of the side ratio: (3/5)² = 9/25; larger area = 27 × (25/9) = 75 cm².

Question 25: What is the value of 3x − 7 when x = 5?

7
9
6
8 (Correct answer)

Correct answer: 8

3(5) − 7 = 15 − 7 = 8.

Question 26: In a DC circuit, electrons flow from which terminal to which?

They do not move
They alternate direction
Positive to negative
Negative to positive (Correct answer)

Correct answer: Negative to positive

Electrons carry negative charge and are attracted toward the positive terminal, flowing from negative to positive.

Question 27: Read the sentence: 'The officer's tenacity in pursuing the mission despite setbacks ultimately led to its success.' What does 'tenacity' most nearly mean?

Persistence (Correct answer)
Recklessness
Obedience
Creativity

Correct answer: Persistence

'Tenacity' means persistent determination or not giving up, which fits the context of succeeding despite setbacks.

Question 28: A technician earns $28 per hour for regular hours and 1.5x that rate for overtime. In a week with 40 regular hours and 8 overtime hours, what are his total earnings?

$1,344
$1,568
$1,456 (Correct answer)
$1,288

Correct answer: $1,456

Regular pay = 40 x $28 = $1,120; overtime rate = $42/hr; overtime pay = 8 x $42 = $336; total = $1,456.

Question 29: Read: 'Sailors in the 18th century used chronometers to determine longitude at sea. Before accurate timekeeping, longitude could not be reliably calculated, and ships frequently ran aground.' What problem did chronometers solve?

Lack of star charts for navigation
Inability to measure latitude
Inability to reliably calculate longitude (Correct answer)
Poor communication between vessels

Correct answer: Inability to reliably calculate longitude

The passage states that accurate timekeeping via chronometers enabled reliable longitude calculation, solving a deadly navigation problem.

Question 30: A cylinder has radius 3 cm and height 10 cm. What is its volume? (Use π ≈ 3.14)

282.6 cm³ (Correct answer)
565.2 cm³
94.2 cm³
188.4 cm³

Correct answer: 282.6 cm³

V = π × r² × h = 3.14 × 9 × 10 = 282.6 cm³.

Question 31: Which set of circumstances would cause carburetor icing?

75 degrees Fahrenheit and 60% relative humidity (Correct answer)
50 degrees Fahrenheit and 50% relative humidity
80 degrees Fahrenheit and 30% relative humidity
90 degrees Fahrenheit and 40% relative humidity

Correct answer: 75 degrees Fahrenheit and 60% relative humidity

Carburetor icing is most likely to occur when the outside air temperature is between 20°F and 70°F (or 0°C and 20°C) and the relative humidity is above 50%. The evaporative cooling effect inside the carburetor can drop the air temperature significantly, causing moisture to freeze even when ambient temperatures seem warm. Thus, 75 degrees Fahrenheit and 60% relative humidity falls within the high-risk conditions for ice formation.

Question 32: Factor completely: x² - 9x + 20

(x - 2)(x - 10)
(x - 4)(x - 5) (Correct answer)
(x - 4)(x + 5)
(x + 4)(x + 5)

Correct answer: (x - 4)(x - 5)

Find two numbers that multiply to 20 and add to -9, which are -4 and -5.

Question 33: Read: 'Unlike surface vessels, submarines must manage buoyancy precisely to maintain depth. Too much positive buoyancy causes uncontrolled ascent; too much negative buoyancy causes descent.' Which conclusion is best supported?

Neutral buoyancy keeps a submarine at a stable depth (Correct answer)
Positive buoyancy is always desirable
Submarines sink if their engines fail
Submarines rely solely on propellers for depth control

Correct answer: Neutral buoyancy keeps a submarine at a stable depth

The passage implies a balance between positive and negative buoyancy — neutral buoyancy — is needed to maintain depth.

Question 34: A passage recounts how the Doolittle Raid of 1942, though causing minimal physical damage, provided a major psychological boost to American morale during a difficult period of the war. What is the main idea?

The raid's significance lay in its morale impact rather than its material damage (Correct answer)
The Doolittle Raid destroyed key Japanese military installations
The raid proved that aircraft carriers were obsolete
Jimmy Doolittle was the most decorated pilot of World War II

Correct answer: The raid's significance lay in its morale impact rather than its material damage

The passage emphasizes that the raid's true importance was its psychological effect on American morale, not its physical damage.

Question 35: A passage's main idea differs from its topic in that the main idea:

Is a single word or short phrase naming the subject.
Is always found in the first sentence of the passage.
Makes a specific claim or assertion about the topic. (Correct answer)
Is stated only in the concluding paragraph.

Correct answer: Makes a specific claim or assertion about the topic.

The topic names the subject; the main idea makes a specific point or argument about that subject.

Question 36: Simplify the polynomial expression: (4a² + 3ab - 6b²) - (a² - 2ab + 3b²)

3a² + ab - 9b²
3a² + ab - 3b²
3a² + 5ab - 9b² (Correct answer)
5a² + ab - 3b²

Correct answer: 3a² + 5ab - 9b²

To simplify, distribute the negative sign to the second polynomial: - (a² - 2ab + 3b²) becomes -a² + 2ab - 3b². Now, rewrite the entire expression and combine like terms: (4a² - a²) + (3ab + 2ab) + (-6b² - 3b²). This simplifies to 3a² + 5ab - 9b².

Question 37: What is the length of the hypotenuse of a right triangle with legs of 9 and 12?

15 (Correct answer)
√225 − 81
18
21

Correct answer: 15

c² = 9² + 12² = 81 + 144 = 225, so c = 15 (a 3-4-5 triple scaled by 3).

Question 38: Read: 'The petty officer spoke with unimpeachable authority on the subject, having served in that capacity for over two decades.' The word 'unimpeachable' most nearly means:

Derived from textbooks
Informal and casual
Beyond reproach or challenge (Correct answer)
Questionable and disputed

Correct answer: Beyond reproach or challenge

'Unimpeachable' means not able to be doubted or questioned; the officer's long experience reinforces this authority.

Question 39: How many times does Gear C rotate in 3 minutes if Gear A is moving at 10 rotations per minute?

3 times
30 times (Correct answer)
1.7 times

Correct answer: 30 times

To determine the rotations of Gear C, we need to know the gear ratios between A, B, and C. Assuming a common gear setup where the final gear (C) rotates at the same speed as the initial gear (A) due to specific gear sizes (e.g., A and C are the same size, and B is an idler gear or the ratios cancel out), if Gear A rotates at 10 rotations per minute (RPM), then Gear C also rotates at 10 RPM. Over 3 minutes, Gear C would complete 10 rotations/minute * 3 minutes = 30 rotations.

Question 40: A spring with a spring constant of 50 N/m is compressed 0.4 m from its natural length. How much potential energy is stored in the spring?

20 J
10 J
40 J
4 J (Correct answer)

Correct answer: 4 J

Elastic potential energy = ½kx² = ½ × 50 × 0.16 = 4 J.

OAR (Officer Aptitude Rating) Test

The OAR (Officer Aptitude Rating) Test exam validates essential knowledge and skills required for certification or licensure in this field.

Questions

60 min

Time Limit

60%

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

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