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Answer:
A) 1.3×10^37 ergs
B) 1.435×10^3 mm
Step-by-step explanation:
A) The quantity is found by multiplying the rate by the time:
(3.9×10^33 ergs/s)×(3.25×10^3 s) = 1.2675×10^37 ergs ≈ 1.3×10^37 ergs
The least-precise contributor to the calculation has 2 significant digits, so we need to round the result to 2 significant digits.
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B) A fine human hair is more than 40×10^-3 mm in diameter, so the distance 1.435×10^-3 mm is completely unreasonable for railroad track spacing. The space between rails is closer to 1.4 meters. So 1.435×10^3 mm is a better measurement.