Two railway convoys travel in opposing directions at 60 km/hr and 90 km/hr, possessing lengths of 1.10 km and 0.9 km respectively. How many seconds does the slower convoy take to pass the faster convoy_________?
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Answer: C. 48
Explanation
Adding the opposing speeds of both railway convoys gives a relative speed of 150 kilometers per hour. Converting the relative speed yields approximately 41.67 meters per second for the passing rate. Dividing the total combined length of 2.0 kilometers by the relative speed results in exactly 48 seconds. Relative speed when objects travel in opposite directions is calculated by adding their individual speeds together. Total distance in train crossing problems equals the sum of the lengths of both moving convoys. Time taken to pass is calculated by dividing total distance by relative speed, with proper unit conversions.
Railway signaling and scheduling systems require precise relative speed calculations to ensure track safety. Traffic engineering applies relative motion physics to analyze vehicle passing times on highways. This physics problem tests the combination of unit conversion, relative velocity, and time-distance formulas. Option A underestimates the passing time by using an incorrect relative speed calculation. Option B represents a minor arithmetic error in dividing the combined train lengths by the speed. Option D slightly overestimates the required passing duration due to rounding discrepancies.
- Subject
- Mathematics
- Category
- Mathematics
- Topic
- —
- Difficulty
- medium
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