OAR Cheat Sheet 2026

The 30 highest-yield OAR facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which component opposes changes in current flow in a circuit? → Inductor
2. In a first-class lever, the fulcrum is located 2 ft from the load and 6 ft from the effort. If the load weighs 150 lb, what effort is required to balance it? → 50 lb
3. An inclined plane is 10 ft long and 3 ft high. What is its ideal mechanical advantage? → 3.33
4. If x = -3, what is the value of 2x² - 5x + 1? → 34
5. 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
6. What happens to the total resistance when resistors are connected in parallel? → It decreases below the smallest individual resistor
7. A rectangular prism has a length of 8 cm, a width of 5 cm, and a height of 3 cm. What is its surface area? → 158 sq cm
8. Which of the following is the greatest common factor (GCF) of 48 and 36? → 12
9. If the flow rate through a pipe is 12 liters per minute and the cross-sectional area of the pipe is 4 cm², what is the flow velocity? → 0.5 m/s
10. Which of the following best defines the property of a fluid known as viscosity? → The fluid's internal resistance to flow.
11. What is the value of 3/4 + 5/8? → 11/8
12. A rope is cut into pieces of 2.5 feet each. If the original rope is 17.5 feet long, how many pieces are cut? → 7
13. A sailor earns $2,400 per month. If 25% is withheld for taxes, what is the take-home pay? → $1,800
14. In a venturi meter, what happens to the fluid pressure in the constricted (narrow) section compared to the wider section? → Pressure decreases
15. An aircraft travels 480 miles in 1.5 hours with a tailwind and 480 miles in 2 hours against the wind. What is the speed of the wind? → 40 mph
16. Which simple machine is represented by a doorstop being pushed under a door? → Wedge
17. Expand and simplify: (2x + 3)(x - 7) → 2x² - 11x - 21
18. Which class of lever has the effort applied between the fulcrum and the load? → Third class
19. If a fuel tank holds 480 gallons and is currently 5/8 full, how many gallons of fuel are in the tank? → 300 gallons
20. If 7x = 56, what is the value of x? → 8
21. The legs of a right triangle measure 9 and 12. What is the length of the hypotenuse? → 15
22. A passage describes both the advantages and disadvantages of a new naval radar system. What is the author's most likely purpose? → To provide a balanced analysis so readers can draw an informed conclusion
23. Which sentence contains a detail that is irrelevant to a passage about the importance of clear communication during naval operations? → The U.S. Naval Academy was founded in 1845.
24. Which set of circumstances would cause carburetor icing? → 75 degrees Fahrenheit and 60% relative humidity
25. If the ratio of officers to enlisted personnel is 1:8 and there are 252 total, how many officers are there? → 28
26. Read the sentence: 'The commander issued a **succinct** briefing, covering all key points in under five minutes.' What does 'succinct' most nearly mean? → Concise
27. What is the primary reason that airplane wings generate lift, as related to fluid dynamics? → Air moves faster over the curved top surface, creating lower pressure above the wing
28. In a DC circuit, electrons flow from which terminal to which? → Negative to positive
29. A tank is filled with water to a height of 5 meters. What is the approximate gauge pressure at the bottom of the tank? (Use g = 9.8 m/s²) → 49,000 Pa
30. A fixed pulley is attached to the ceiling to lift a load. What is the primary advantage of this single fixed pulley? → It changes the direction of the applied force