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The speed of a 120 meter long train is 54 km per hour. it crosses a bridge in 32 seconds.

1. determine the length of the bridge in kilometer.
2. determine the speed of the train in kilometer per hour to cross the bridge in 24 seconds.
3. determine the length of the train when the speed of the train is 54 km per hour and it cross the bridge in 36 seconds.

Respuesta :

1. The length of the bridge is 360 m.

2. The speed of train in km/hr to cross the bridge in 24 s is 72 km/hr.

3. The length of the train when it cross the bridge in 36 seconds is 540 m.

What is speed?

Speed is the ratio of distance traveled and the time taken to cover that distance.

1.

The speed of train m/s is 54 x 5/18 = 15 m/s

The train crosses the bridge in 32 s, distance traveled by train will be

=32 x 15 =480m

The length of the bridge = (480 -120) =360 m

Thus, the length of the bridge is 360 m.

2.

Speed of train in m/s to cross the bridge in 24 s

= 480/24 = 20 m/s

Speed in km/hr =20 x 18/5 = 72 km/hr

Thus, Speed of train in km/hr to cross the bridge in 24 s is 72 km/hr.

3.

Speed of train in m/s =15 m/s

Train crosses the bridge in 36 s, then length of train will be

= 15 x 36m = 540m

Thus,  the length of the train when it cross the bridge in 36 seconds is 540 m

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