Plz answer it as soon as possible if possible

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Train accelerates with a = 0.2 m/s² , t = t₁ and v= v₁

v=u + at and v₁=0.2t₁ or t₁= 0.2 v₁ /2 …(1)

s=ut+(1/2)at²

Case II:

v₂=v₁+a₂t₂(train is retarding and s =s₁)

s₁=1/2 x 0.2 x t₁²

v₂=v₁+a₂t₂

0 = v₁+0.4t₂

t₂=–v1/0.4 …(2)

s₂=v₁t₂ +(1 /2) x a₂t₂²

t=t₁+t₂ = 30 min = 1800

t₁=1200 secs and t₂ = 600 secs

substituting a, v and t in (1) and (3), we get 

s₁ = 144 km and s₂= 72 km

Total distance s= s₂+ s₂

s=216km

Regards

Arun (askIITians forum expert)