Question
A passenger sitting in a train A moving at 90 ~km / h observes another train B moving in the opposite direction for 8 ~s . If the velocity of the train B is 54 ~km / h , then length of train B is :
BITSAT
Physics
Motion In One Dimension
2023
BITSAT 2023 (Memory Based Paper 2)
BITSAT Physics Question (2023) — Solution
Options
- A. 80 ~m
- B. 200 ~m
- C. 120 ~m
- D. 320 ~m
Answer
D. 320 ~m
Step-by-step solution
Velocity of train A \( V _ A =90 km hr =90 5 18 =25 ~m / s \) Velocity of train B \( V _ B =54 km hr =54 5 18 =15 ~m / s \) Velocity of train B w.r.t. train \( aligned A= V _B & - V _A \\ & =15-(-25) m / s \\ & =40 ~m / s aligned \) Time of crossing \(= length of train relative velocity \) \((8)= 40 \) \( =8 40=320\) meter.
Related: Physics — Motion In One Dimension · All PYQ Banks