Question

Difficulty: MediumExplicit Main Idea

Hydraulic accumulators serve as critical energy storage devices that maintain essential system pressure in tactical vehicle hydraulic circuits. When the engine-driven hydraulic pump operates under normal conditions, excess fluid compresses a nitrogen gas bladder within the accumulator shell. If sudden steering demands exceed pump output or if the primary pump fails entirely, this compressed gas forces stored fluid back into the lines to power steering and braking actuators. While standard fluid reservoirs only hold unpressurized reserve oil, accumulators guarantee immediate high-pressure reserve power during critical mechanical emergencies.

Which of the following statements best expresses the main idea of the passage?

  1. A
    All tactical vehicle emergency subsystems depend entirely on nitrogen gas for their mechanical power.
  2. Hydraulic accumulators store pressurized fluid to maintain necessary operational pressure in vehicle hydraulic systems.Answer
  3. C
    An engine-driven hydraulic pump compresses a nitrogen gas bladder during normal operating conditions.
  4. D
    Standard fluid reservoirs fail during emergencies because they hold only unpressurized oil.

Answer

Hydraulic accumulators store pressurized fluid to maintain necessary operational pressure in vehicle hydraulic systems.
The correct option captures the central topic explicitly introduced in the first sentence and developed throughout the paragraph: hydraulic accumulators act as energy storage components that maintain necessary hydraulic pressure.

Step-by-Step Solution

1
Read the passage and locate the explicit topic sentence.
The opening sentence directly states that hydraulic accumulators serve as critical energy storage devices maintaining essential system pressure in tactical vehicle hydraulic circuits.
Explicit main ideas in technical expository texts are typically stated directly in the lead or summary sentences.
2
Evaluate the remaining sentences to verify they function as supporting details.
Sentences 2, 3, and 4 explain how the accumulator charges, how it discharges under high demand or failure, and contrast it with unpressurized reservoirs.
Supporting details provide mechanisms and context that reinforce the primary claim without replacing it.
3
Match the core claim to the option that accurately paraphrases the entire passage's scope.
The statement expressing that hydraulic accumulators store pressurized fluid to maintain necessary operating pressure perfectly aligns with the explicit topic sentence.
The correct answer must encompass the entire passage rather than single steps or secondary comparisons.

Key Concept

Explicit Main Idea Identification
Estimated Time:1m 0s
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