A train of length 150 in is going to north with a speed of 10ms-1. A parrot flies 5 ms-1 toward south parallel to the railway line. The time taken by parrot to cross the train is:
Correct answer: B. 10 s
- A. 8 s
- B. 10 s
- C. 12 s
- D. 15 s
Explanation
To find the time taken by the parrot to cross the train, consider their relative speeds. The train is moving north at 10 m/s, and the parrot is flying south at 5 m/s. The relative speed of the parrot with respect to the train is the sum of their speeds, which is 15 m/s since they are moving in opposite directions. The length of the train is 150 meters. Using the formula t = S/vr, where S is the distance (150 m) and vr is the relative speed (15 m/s), we get t = 150/15 = 10 seconds. Therefore, the correct answer is 10 seconds. Options 8 s, 12 s, and 15 s are incorrect as they do not accurately reflect the relative motion between the parrot and the train.
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