A train of length 220 metres crosses an electric pole in 11 seconds and…
2021
A train of length 220 metres crosses an electric pole in 11 seconds and crosses another train of the same length travelling in the opposite direction in 8 seconds. What is the speed of the second train?
- A.
35 m/s
- B.
42 m/s
- C.
46 m/s
- D.
37 m/s
Attempted by 19 students.
Show answer & explanation
Correct answer: A
Calculate the speed of the first train (v1):
v1 = Length / Time to cross a pole = 220 m / 11 s = 20 m/s.
Determine relative speed (v_rel) when crossing the second train:
Relative speed = (Length of train 1 + Length of train 2) / Time to cross
v_rel = (220 m + 220 m) / 8 s = 440 m / 8 s = 55 m/s.
Calculate the speed of the second train (v2):
Since they move in opposite directions, relative speed = v1 + v2.
55 m/s = 20 m/s + v2
v2 = 55 - 20 = 35 m/s.
Final Answer: Option 1 (35 m/s)