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Question

Difficulty: MediumRecognizing Implied Cause and Effect

During a midsummer heatwave across an arid valley, track inspectors discovered that continuous steel rails along unshaded curves had buckled outward into lateral wave patterns. Maintenance crews had anchored these jointless steel rails tightly to concrete ties during midwinter when temperatures hovered near freezing. Under the intense midday heat exceeding 105°F, internal compressive stress accumulated throughout the rigid metal.

Based on the passage, what most likely led to the outward buckling of the steel rails?

  1. A
    The structural failure of concrete ties under the excessive weight of heavy freight cars
  2. The expansion of steel in extreme heat after being tightly secured during freezing conditionsAnswer
  3. C
    The track inspectors conducting physical surveys along unshaded curves of the rail line
  4. D
    The physical distortion of the steel tracks triggering rapid temperature rises in the valley

Answer

The expansion of steel in extreme heat after being tightly secured during freezing conditions
The passage states that the jointless rails were anchored tightly during freezing winter weather and later subjected to extreme summer heat exceeding 105°F, building severe compressive stress. The implied cause of the buckling is that the heated steel attempted to expand but, being rigidly constrained, was forced outward into lateral wave patterns.

Step-by-Step Solution

1
Identify the timeline and initial physical state described in the passage
Jointless steel rails were anchored tightly to concrete ties in near-freezing winter temperatures.
Establishing the initial baseline condition explains how the rails were constrained when installed.
2
Analyze the environmental change and the resulting physical reaction
Exposure to temperatures above 105°F caused compressive stress to build within the constrained metal.
Connecting temperature rise to internal stress reveals the underlying physical mechanism.
3
Deduce the implied causal relationship that produced the observed outcome
Because the rails were anchored tightly without room to expand, the heat-induced expansion forced the metal to buckle outward.
Synthesizing the premises demonstrates that constrained thermal expansion caused the structural deformation.

Key Concept

Implied cause and effect requires linking unstated physical or sequential relationships based on given premises.
Estimated Time:1m 0s
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Topics

Recognizing Implied Cause and Effect

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