Two trains, each of length 500 meters, start off from rest with speeds of 60 km/h and 45 km/h respectively. After how many minutes does the first train cross the second one?

Two trains, each of length 500 meters, start off from rest with speeds of 60 km/h and 45 km/h respectively. After how many minutes does the first train cross the second one?

Explanation

 Convert the speeds of the trains from km/h to m/s

1 km/h = 1000 m/3600 s

Speed of the first train = 60 km/h = (60,000 m/3600 s) m/s = 16.67 m/s.

Speed of the second train = 45 km/h = (45,000 m/3600 s) m/s = 12.50 m/s.

Relative speed = Speed of the first train - Speed of the second train = 16.67 m/s - 12.50 m/s = 4.17 m/s.

Distance = Length of the second train = 500 meters.

Using the formula:

Distance = Speed × Time

Time = Distance / Relative speed = 500 meters / 4.17 m/s = 120.05 seconds.

To convert the time from seconds to minutes, we divide by 60:

Time in minutes = 120.05 seconds / 60 = 2 minutes (approximately).

Therefore, the first train will cross the second train after approximately 2 minutes.