Two trains 140 meters and 160 meters long are running at the speeds of 60 km/h and 40 km/h respectively in opposite directions on parallel tracks. What is the time taken by them to cross each other completely? MCQ with Answer and Explanation
Two trains 140 meters and 160 meters long are running at the speeds of 60 km/h and 40 km/h respectively in opposite directions on parallel tracks. What is the time taken by them to cross each other completely?
A. 12 seconds
B. 10.8 seconds
C. 9 seconds
D. 10 seconds
Answer: Option B
Solution (By JKSSB Mock Tests)
Total distance to be covered = 140 + 160 = 300 meters. Relative speed = 60 + 40 = 100 km/h = 100 * (5/18) = 250/9 m/s. Time = Distance / Speed = 300 / (250/9) = 300 * 9 / 250 = 10.8 seconds.
A sound wave travels at a speed of 330 m/s. If the echo of a sound is heard from a wall after 2 seconds, find the distance of the wall from the source.
Explanation:
Total distance traveled by the sound wave to the wall and back = Speed * Time = 330 * 2 = 660 meters. Distance to the wall = 660 / 2 = 330 meters.
No comments yet. Be the first to start the discussion!