Question

A subway train starts from rest and accelerate at 2m/s^2 for 10sec and then goes at constant speed for30sec and then decelerate at 4m/s^2 till rest, find the distance between stations.

Answer 1

the distance between stations in above image

Answer 2

step 1 ::::; a = 2 m/s ; t = 10 sec ; v(initial) = 0

from this information :::: s = ut + 1/2 at^2

                                         = 100m

v(final) = u + at = 20 m/s

step2

then it is given that  a = 0  AND t = 30sec

to this we have to find it its v initial which is equal to the v final of step 1

therefore its v initial = 20m/s

therefore S = ut + 1/2 at^2

                    = 20  x 30 = 600 m

step3

a = 4m/s and v final = 0

from v^2 = u^2- 2as

         0 = (20)^2  - 2(4)S

         S= 50m

now you can sind the individual distances between the stations