NUMERICAL PROBLEM BASED ON MOTION WITH UNIFORM ACCELERATION

Asked by  | 1st Dec, 2008, 05:48: PM

Expert Answer:

velocity of mail train u1= 108Km/hr = 30m/s
velocity of passenger train u2= 36m/s = 10m/s
Acceleration =a= -1m/s2
Distance between the two trains = 250m

According to the equation of motion: 2aS = v1 2-u1
              Where v 1   = 0 m/s    (train stops after brakes)

Hence we get : S = 450m/s that is the distance moved by the mail train before stopping                                        
 S = u t   + 1/2 at2

where t is the time taken to stop.: t = 30sec

In the same time the passenger train travels a distance of 30 x 10 = 300m.

The total distance between the passenger train and mail train is 300+250m = 550m but the mail train travels only 450 m . hence the collision is saved.

 

Answered by  | 2nd Dec, 2008, 08:20: PM

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