Q 11-02-080JEE MainJEE Main 2023 (13 Apr, Shift 2)Easy
A passenger sitting in a train A moving at $90\ \text{km h}^{-1}$ observes another train B moving in the opposite direction for $8$ s. If the velocity of the train B is $54\ \text{km h}^{-1}$, then length of train B is
Answer: (B) $320\ \text{m}$
Relative speed $=90+54=144\ \text{km h}^{-1}=40\ \text{m s}^{-1}$. Length $=40\times8=320\ \text{m}$.
Solution by Sreeraj P, M.Sc Physics