Problem on trains

**Problem on trains**

1 Suppose there are two trains A and B having length a metre and running at a speed of x m/sec and y m/sec respectively. Here two cases arise-

Q.1 If a train of length 120 metre crosses another train of length 180 metre running in the same direction at a speed of 40km/hr. and 76km/hr respectively. Find the time taken to cross each other.

Sol-

2 when a train of length a metre having a speed of x m/sec. Crosses a bridge/tunnel platform etc. of length b meter, then

Q.1 Find out the time a train will take to cross a platform of 210 metre running at a speed of 72km/hr.

Sol- Data inadequate (length of train is required)

Q.2 A train of length 100m crosses a bridge of length 200m in sec. what is the speed of the train is km/hr.?

Sol

Stationary man etc. then time taken.

Q.1 A train crosses a tree in 12 sec at a speed of 54km/hr. Find the length of train.

Sol-

4 When a train of length a metre having speed x m/sec. crosses a moving object of negligible length having speed Y m/sec. there are two cases.

(a) when object is moving towards the train-

(b) when object is moving with the train in the same direction-

Q.1 A train of length 150m, crosses a man running it at 9km/hr. if speed of train is 45km/hr. what is the time taken by train to cross the man?