Question

A 120 meter long train is running at a speed of 64 km/hr. in how much time will it cross a man running at a speed of 10 km/hr in the same direction? 1.

Answer 1

➡️Relative velocity V(rel)=6410=54km/hr ➡️V(rel)=54×5/18=15m/s ➡️t=120/15=8sec

Answer 2

relative speed = 64-10 = 54 km/hr
54 × 5/18 = 15m/s
so time = distance / speed
time = 120/15 = 8 m/s