Question

The Cotton Express runs at a speed of 90 kmph. Its length is 240 m and it passes a man, walking at 10 kmph in the same direction, in "a" seconds. Determine the value of "a".

Answer 1

Given that The Cotton Express runs at a speed of 90 kmph.

Its length is 240 m

it passes a man, walking at 10 kmph in the same direction, in "a" seconds.

Since man walks in the same direction relative velocity = difference of two velocities

= 90-10 = 80 kmph

= 22.222 m/sec.

When it crosses the man, distance travelled = length of the train = 240 m.

Hence time taken to cross = 240/22.222 = 10.80 sec