Sunday
March 26, 2017

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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 {\rm m/s}^2 for 20 {\rm s}. It then proceeds at constant speed for 1100 {\rm m} before slowing down at 2.2 {\rm m/s}^2 until it stops at the station.

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

• Physics - ,

1st acceleration: s = .5 * 1.1 * 400 = 220m
velocity attained: 1.1*20 = 22m/s

2nd acceleration: 22m/s / 2.2m/s^2 = 10s
2nd distance = .5 * 2.2 * 100 = 55m

distance = 220 + 1100 + 55 = 1375m

• Physics - ,

It takes 80 seconds to travel between stations

• Physics - ,

How did you get 80 seconds?