How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr?

Given Data

• Train length = 500 m
• Train speed = 63 km/hr
• Man walking in the same direction at 3 km/hr
• Required: time for the train to completely cross the man

Step 1: Relative speed (same direction ⇒ difference)v_rel = 63 − 3 = 60 km/hr = 60 × (5/18) = 16.6667 m/s

Step 2: Time = distance ÷ speedt = 500 ÷ 16.6667 ≈ 30 s

Checks & Common Pitfalls

• Use difference of speeds for same-direction motion.
• When crossing a man, distance equals the train length only.
• Convert km/hr to m/s by × 5/18.

Final AnswerThe required time is 30 s.