Question

a train starts from rest and moves with a constant acceleration for 2 minutes and covers a distance of 400 m. Find the acceleration of the train.

Answer 1

Hello !
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here , 
u = 0 m/s
t  = 2 x 60 = 120 seconds 
s = 400 m
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s       = ut + 1/2 at²
 400  = 1/2 at²
 400  = 1/2 a x 120 x 120
 4      = 1/2 x 12 x 12 x a 
 a      =  4 x 2 /144
         =  8 /144
         =  0.05 m/s²
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Answer 2

Initial velocity = u = 0 m/s
Time =  t  =  120 seconds 

distance traveled = s = 400 m

equation of motion :-

s    = ut + 1/2 at²

 400  = 1/2 at²

 400  = 1/2 a x 120 x 120

 4 = 1/2 x 12 x 12 x a 

 a =  8 /144
  =  0.05 m/s²

acceleration of the train =  0.05 m/s²