Q. A $120\ m$ long train is moving in a direction with speed $20\ m/s$. A train $B$ moving with $30\ m/s$ in the opposite direction and $130\ m$ long crosses the first train in a time
A) $6\ s$
B) $36\ s$
C) $38\ s$
D) None of these
Explanation
(d) Total distance $= 130 + 120 = 250\ m$
Relative velocity $= 30 - ( - 20) = 50\ m/s$
Hence $t = 250/50 = 5\ s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.