Physicshard · Past Paper
Two trains 120m and 80m long are running in opposite directions with velocities 42 km/h and 30 km/h. The time they take to cross each other is:
A10 s
B15 s
C20 s
D25 s
✓ Correct Answer: A — 10 s
Relative velocity = 42 + 30 = 72 km/h = 20 m/s. Total distance = 120 + 80 = 200m. Time = 200 / 20 = 10s.
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