Q12 of 25 Page 130

A train starting from rest attains a velocity of 20m/sec in 2 minutes. Assuming that the acceleration is uniform find (i) the acceleration. (ii) distance travelled by train while it attained this velocity.

As, 1min = 60s

So, 2min = 2 × 60s = 120s


According to First equation of motion


v = u + at


20m/s = 0m/s + a(120s)


m/s2 = a


According to Third equation of motion


v2 = u2 + 2as


(20m/s)2 = (0m/s)2 + 2 × m/s2 × s


400 = s


⇒ s = 1200m


∴ the distance travelled by the train is 1200 m.


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