A TRAIN IS MOVING ON A STRAIGHT TRCK AND TRAVELS AT A SPEED OF 72KM/HR AND PASSES A POLE BIN 3 SECONDS. FIND THE TJME TAKEN TO PASS A BRIDGE OF LENGTH 540m

It must be a rather short train if it passes a pole in three seconds.

72 km/h = 20 m/s. The length of the train must be
L = 20 m/s * 3 s = 60 meters

To cross a bridge 540 m long, you have to add the times it takes the engine to cross (540/20 = 27 seconds) and the three seconds needed for the rest of the train to reach the end. That is a total of 30 seconds.

To find the time taken for the train to pass a bridge of length 540m, we need to consider the relative speeds of the train and the bridge.

Given:
- Speed of the train = 72 km/hr
- Time taken by the train to pass a pole = 3 seconds
- Length of the bridge = 540m

First, let's convert the speed of the train from km/hr to m/s:
- 72 km/hr = (72 * 1000) m / (60 * 60) s = 20 m/s

Now, since the train is passing both the pole and the bridge, we need to consider the additional distance it covers when passing the bridge.

The distance covered by the train in 3 seconds when passing the pole is its speed multiplied by the time:
- Distance = Speed * Time = 20 m/s * 3 s = 60 m

So, the train covers an additional distance of 60 m when passing the bridge.

To find the time taken to pass the bridge, we need to calculate the relative speed of the train and the bridge:
- Relative Speed = Train Speed - Bridge Length
= 20 m/s - 540 m

Now, we can calculate the time taken to pass the bridge using the relative speed:
- Time = Distance / Relative Speed
= 540 m / (20 m/s - 540 m)
= 540 m / (-520 m/s)
= -1.038 s

Since distance and time cannot be negative, we can conclude that the train passed the bridge instantaneously (i.e., it took no additional time).

Therefore, the time taken to pass the bridge is negligible.