To determine the velocity of the train, we can use the relative velocity concept. The relative velocity is the combined effect of the velocities of the man and the train.
Given: Length of the train (L) = 100 m Velocity of the man (v_m) = 5 km/hr = (5 * 1000) m/3600 s = 5/3.6 m/s ≈ 1.39 m/s Time taken to cross the train (t) = 7.2 s
Let the velocity of the train be v_t.
When the man crosses the train, he covers the length of the train with the combined velocity of himself and the train. So, the relative velocity is the sum of their velocities:
Relative velocity = v_t + v_m
We can use the formula: relative velocity = distance/time
(v_t + v_m) = L/t
Now we can substitute the given values:
(v_t + 1.39) = 100/7.2
v_t + 1.39 = 13.89
v_t = 13.89 - 1.39
v_t ≈ 12.5 m/s
Therefore, the velocity of the train is approximately 12.5 m/s.