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A light-rail train going from one station to the next on a straight section of track accelerates from rest at 1.1 m/s2 for 20 s. It then proceeds at constant speed for 1100 m before slowing down at 2.2 m/s2 until it stops at the station.

How much time does it take the train to go between the stations?

Express your answer using two significant figures.

Verified Answer :

AL2006


-- Accelerating for 20 seconds takes it 20 seconds.
During that time, it reaches aspeed of  (1.1 x 20) = 22m/s .

-- Moving at 22 m/s, it takes  (1100 / 22) = 50 seconds to cover 1100 m.

-- To go from 22 m/s to a stop takes  (22 / 2.2) = 10 seconds .

Total time = (20 + 50 + 10) = 80 seconds.


The slightly-more-interesting question concerning the same train is:
What is the total distance between the two stations ?


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