2023 · Q73
train starting from rest with a uniform acceleration attains a speed of 108 km/h in 5 minutes. The distance covered by the train in attaining the speed is
General SciencePhysics
- A9000
- B4500
- C355
- D108
Explanation
With uniform acceleration from rest, distance equals average velocity times time. Here v = 108 km/h = 30 m/s and t = 5 minutes = 300 s, so s = (0 + 30)/2 x 300 = 4,500 m. The naive speed-times-time calculation gives 9,000 m because it ignores the acceleration. Hence B.