MCAT Physics Question 33: Answer and Explanation
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Question: 33
3. A 20 m steel rod at 10°C is dangling from the edge of a building and is 2.5 cm from the ground. If the rod is heated to 90°C, will the rod touch the ground? (Note: α = 1.1 × 10-5 K-1)
- A. Yes, because it expands by 3.2 cm.
- B. Yes, because it expands by 2.6 cm.
- C. No, because it expands by 2.2 cm.
- D. No, because it expands by 1.8 cm.
Correct Answer: D
Explanation:
First, find the change in length due to thermal expansion:
Because the rod is originally 2.5 cm above the ground and its length increases by 1.76 cm, we can conclude that it will not touch the ground after the thermal expansion process is completed.