how to solve 2nd part

Asked by lakshyasaxena970 | 7th Jul, 2021, 10:42: PM

Expert Answer:

Part (a)
 
As shown in figure , Train-B has to travel a distance 500 m to overtake Train-A . 
 
Relative velocity of Train-B with respect to train-A is (40-20) = 20 m/s . 
 
Hence time taken to travel 500 m distance = distance / relative velocity = 500 / 20 = 25 s
 
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Part (b)
 
Required acceleration a for train-B to overtake train-A in a time duration of t seconds is determined
from the following equation of motion
 
S = [ uB - uA ] t + (1/2) a t2
 
Where S is distance to be travelled, uA is the initial speed of train-A  and uB is initial speed of train-B 
 
Since both train are moving with same speed ,  [ u- uA ] = 0
 
Hence , we have ,  S = (1/2) a t2   or      a   = ( 2 S ) / t2  
 
acceleration a = ( 2 × 500 ) / (50 × 50 ) = 0.4 m/s2

Answered by Thiyagarajan K | 8th Jul, 2021, 08:32: AM

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